Displaying One Session

Exhibition Foyer Poster Session
Session Type
Poster Session
Date
13.04.2022
Time
09:30 - 10:45
Room
Exhibition Foyer
Session Description
During the Poster Viewing Session, coffee, tea, and refreshments are served in the exhibition area as a courtesy of the ICRS.
Poster Animal Models

P002 - Comparison of Three Cell-Free Matrix Scaffolds Used to Treat Osteochondral Lesions in a Rabbit Model

Presentation Topic
Animal Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

This study compared the macroscopic, histological, and scanning electron microscopy (SEM) characteristics of Chondro-Gide®, MaioRegen®, and poly-D,L-lactide-co-caprolactone (PLCL) cell-free scaffolds enhanced with small-diameter microfractures (SDMs) for osteochondral defects (OCDs) in a rabbit model.

Methods and Materials

In total, 54 knees from 27 rabbits were used in this study. Three rabbits were sacrificed at the beginning of the study to form an intact cartilage control group (group IC). An OCD model was created at the center of the trochlea and SDMs were generated in 24 rabbits. Rabbits with OCDs were divided into four groups (n=6 knees per group) according to the cell-free scaffold applied: Chondro-Gide® (group CG), MaioRegen® (group MA), PLCL (group PLCL), and a control group (group SDM). Half of the rabbits were sacrificed at 1 month after treatment, while the other half were sacrificed at 3 months after treatment. Healed cartilage was evaluated macroscopically (using International Cartilage Repair Society [ICRS] classification criteria) and histopathologically (using modified O’Driscoll scores and collagen staining). Additionally, cell-free scaffold morphologies were compared using SEM analysis.

figure 1 11.10.21.jpg

Results

The histological characteristics of group IC samples were superior to those of all other groups, except group PLCL, at 3 months after treatment (p<0.05). In addition, the histological properties of group PLCL samples were superior to those of group SDM samples at both 1 and 3 months after treatment. Concerning type 2 collagen staining intensity, the groups were ranked from highest to lowest at 3 months after treatment, as follows: group PLCL (30.3±2.6)>group MA(26.6±1.2)>group CG(23.3±2.3)>group SDM(18.9±0.9). SEM analysis showed that the PLCL scaffold elasticity facilitated transmission of mechanical signals to adherent cells; scaffold pores also aided cell attachment and proliferation.

vahdet.jpg

Conclusion

OCDs treated with enhanced SDM using cell-free PLCL scaffolds had superior histopathological and microenvironmental properties, more hyaline cartilage, and more type 2 collagen, compared with those treated using Chondro-Gide® or MaioRegen® scaffolds.

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Poster Animal Models

P003 - Volumetric Growth of Distal Femoral Cartilage and Bone during Murine Postnatal Development follows Gompertz Law

Presentation Topic
Animal Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
R. Sah: Cartilage: Editorial or governing board, Osteoarthritis and Cartilage: Editorial or governing board, GlaxoSmithKline: stockholder, Johnson & Johnson: stockholder, Medtronic: stockholder
ICRS Award
Certificate of Merit

Abstract

Purpose

In skeletally immature individuals, the covering of bone ends includes a layer of epiphyseal and articular cartilage known as the articular–epiphyseal cartilage complex (AECC). Although initially a contiguous cartilaginous element, the AECC encompasses tissue that becomes the articular cartilage, growth plate, and a secondary ossification center (SOC). During postnatal development joint size increases and cartilage thickness decreases, however the mechanisms that dictate cartilage maturation and joint shaping remain undetermined. This study aims to (1) illustrate and qualitatively compare shape changes of the bone-cartilage interface and (2) quantitatively assess and model volumetric growth of the distal femoral SOC during normal murine postnatal development.

Methods and Materials

With IACUC approval, male wild-type CD1 mice (P0, P7, P14, P21, P28, P35, and P42; n=2-3/age) were sacrificed, perfusion fixed, skinned and eviscerated, then dehydrated to 70% ethanol before imaging by micro-computed tomography at (9 μm)3 voxel resolution. Volume of the left distal femur SOC was calculated by semi-automatic segmentation. SOC volume (V(t)) was fit to a Gompertz sigmoid model (V(t)=V(t=P42)*exp(-exp(-k(t-T))) with 3 parameters (V(t=P42): asymptote/mature value, T: time at inflection, k: growth rate coefficient).

Results

Although the SOC was not evident at P0, it increased in size between P7 (0.3±0.1 mm3 ) and P42 (~1900%; 6.4±0.1 mm3 ). The SOC initially formed as a small ellipsoidal structure followed by protrusion of the condyles, and formation of the trochlear ridge and intercondylar notch. Increase in SOC volume followed Gompertz function (R2=0.98, RMSE = 0.4), such that growth was slowest at the start and end of the time assessed, with an inflection point at T=~11 days postnatal and growth rate coefficient of k=0.23 1/days.

20211023_icrs_fig.png

Conclusion

Growth of the murine distal femoral SOC during postnatal development follows a sigmoid model indicating 3 phases of growth: the initial lag, the log, and the diminishing growth phases, where mechanisms of growth and maturation may vary

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Poster Animal Models

P004 - A Protocol for Single-Cell Sequencing the Cell Populations Within the Murine Knee

Presentation Topic
Animal Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
J.Yik & D.Haudenschild: Tesio Pharmaceuticals, Inc - Shareholders.

Abstract

Purpose

Single-cell sequencing has potential to provide unprecedented insight into cell-to-cell communication and complex cross-talk between joint tissues. However, difficulty remains in preparing entire joints for comprehensive scRNA-seq analysis due to the great diversity of tissues. Joints tissues like bone and cartilage consist of calcified weight-bearing matrix sparsely populated by cells, whereas synovium and fat pads are highly cellular tissues, and immune cells may have little or no surrounding matrix. To capture this broad range of cell types we developed a two-stage digestion protocol.

Methods and Materials

Mouse knees from femoral and tibial growth plates were isolated, minced and digested in two stages. To protect softer cells from over-digestion a gentler 1% collagenase-IV (30 mins) digestion was used first. An aggressive digest, 2% collagenase-II (90 mins) followed to free cells within cartilaginous and bony matrix.

After each digest, released cells were strained, and RBCs lysed. 10X Chromium Single Cell Gene Expression platform and Illumina HiSeq 4000 were used. Cell Ranger and Seurat created PCA clustering.

Results

This sequential protocol demonstrated consistency of gene expression between contralateral knees by similar cell-types (Fig. 1a). Both digests are required for comprehensive cell-type identification and inclusion (Fig. 1b).

icrs 2021 fig1.png

A diverse collection of cells was captured by this protocol, with many cell-types from hard and soft tissues shown here by selected signature genes (Fig. 2).

fig5.png

Conclusion

To understand the joint environment, we must understand the roles of all cells present in-vivo. This complex problem is currently best studied using scRNA-seq to assess what is happening at the cellular level. This protocol will be valuable for understanding the in-vivo conditions in which cartilage resides and provide unique insight for the study of joint preservation with age or injury.

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Poster Culture Models

P005 - High-level of expansion combined with IL-1β treatment accelerates development of chondrosenescent phenotype

Presentation Topic
Culture Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Chronic, low-grade inflammation (inflammaging) contributes to the age-dependent deterioration of chondrocytes, or chondrosenescence. The chondrosenescent phenotype includes the development of a senescence associated secretory phenotype (SASP). Using both simulated aging (monolayer expansion) and inflammation, we sought to create an in vitro model that replicates the chondrosenescent phenotype found in patient samples. We hypothesized that treatment of young human articular chondrocytes (HACs) with inflammatory cytokines during monolayer expansion will induce biomarker profiles and ECM production levels similar to that of HACs isolated from aged/OA cartilage.

Methods and Materials

HACs (30 ± 10 years) were treated with 1 ng/mL IL-1β during monolayer expansion. Expression of senescence markers (SA-β-gal and p16) and RNAseq for SASP were measured at each passage. High passage, chondrosenescent HACs were then redifferentiated in pellet culture for 28 days and sGAG production was measured using the DMMB assay and Alcian blue staining.

Results

IL-1β treatment during expansion reduced proliferation (Figure 1), increased expression of SASP factors (Figure 2), and increased expression of senescence markers SA-β-gal and p16 (Figure 1) after 7 passages. SASP markers including MMPs, ILs and CXCLs were higher in IL-1β treated samples at P8 (Figure 2a). Expression of SASP markers decreased over time but remined 2-3 orders of magnitude higher in IL-1β treated samples. (Figure 2b). When redifferentiated in pellet culture, matrix production was lower in treated and untreated P7 chondrocytes compared to P4. IL-1β treatment reduced ECM production to levels comparable to OA chondrocytes (not shown).

figure1_icrs.pngfigure2_icrs.png

Conclusion

Treatment with IL-1β during monolayer expansion decreased proliferative potential of HACs after the 4th passage and accelerated expression of SASP and other senescence markers, making it a viable system to model and study chondrosenescence.

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Poster Culture Models

P006 - Establishment of an Ex Vivo Model of Inflammatory Osteoarthritis with Human Osteochondral Explants

Presentation Topic
Culture Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Osteoarthritis (OA) is the most common degenerative joint disease without clear pathophysiological mechanism and effective drugs for treatment. Though various animal models are existing, the translation of these models into clinics remains difficult due to species differences. To advance the clinical relevance of research data, a preclinical OA model with human samples is indispensable.

Methods and Materials

In this study, an ex vivo inflammatory OA model was induced using explants from human OA femoral head. Effects of treatment with different concentrations of IL-1β and TNF-α were compared after 3- and 7-day culture duration. The samples were assessed histologically (n = 3/group), biochemically (n = 6-11/group), and transcriptionally (n = 6-8/group).

Results

In the inflammatory OA groups, the gene expression levels of cartilage catabolism (MMP1, MMP3), and inflammation (IL-6, IL-8) markers were significantly upregulated, while the anabolic genes (COL2, ACAN, PRG4) were downregulated compared with the control group. The release of cytokines (IL-6, IL-8) and nitric oxide (NO) in conditioned medium was also upregulated in the inflammatory OA groups. The Safranin O/Fast Green staining showed that the degradation of proteoglycan in the superficial zone cartilage presented a positive correlation with culture duration and concentration of IL-1β and TNF-α. Cell viability in the cartilage tissue was > 85% and comparable among all groups. For establishment of human osteochondral explant inflammatory OA model, 1 ng/mL IL-1β + TNF-α were enough to induce a mild inflammatory OA condition; 5 ng/mL IL-1β + TNF-α induced a more profound inflammatory and catabolic effect; 10 ng/mL IL-1β + TNF-α showed a similar effect as 5 ng/mL.

Conclusion

The results indicate that an ex vivo OA model of inflammation and degeneration was successfully established using osteochondral explants from human femoral head. This model can be used to elucidate the in-depth mechanism of inflammatory OA, and to screen new drugs for its treatment.

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Poster Culture Models

P007 - In Vitro Modelling of Human Cartilage: Comparing Traditional Culture Methods with Pregenerate Organ-on-a-Chip System

Presentation Topic
Culture Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Julie Rosser is the CEO of Pregenerate GmbH Syed Faheem Ali is the COO & Microfabrication Engineer of Pregenerate GbmH

Abstract

Purpose

In vitro modelling of human cartilage is commonly used to understand injury and disease in the tissue and to test treatment options. Organ-on-a-chip (OOAC) is an emerging modelling technology, incorporating cell culture chambers and microfluidics, that seeks to improve current modelling capabilities by increasing physiological relevance. Here, we assess the Pregenerate OOAC system to investigate human chondrocyte responses to pro-inflammatory stimuli cf. traditional chondrocyte culture techniques.

Methods and Materials

The Pregenerate OOAC consists of a central cell chamber (volume: 7.5µl) connected to a medium channel with an inlet at either end; six of such culture systems are contained on one chip (Figure 1A). Chondrocytes were isolated from macroscopically intact cartilage obtained during knee arthroplasty (n=5) and culture-expanded in monolayer to passage 2. Chondrocytes were encapsulated in Fibrin hydrogel and 2,200 chondrocytes loaded into each cell chamber of the microfluidic chips. Parallel cultures were set in high-density pellets (200k cells/pellet) or in monolayer (5000 cells/cm2). After 21 days, cultures were stimulated with a pro-inflammatory cocktail (50ng/ml TNF-α, 10ng/ml IL-1β and 25ng/ml IFN-γ) for 24 hours prior to assessing gene expression levels of COL1A1, COL2A1, COL10, ACAN, SOX9, MMP1, MMP3, MMP13 and ADAMTS-5.

Results

Fluorescence microscopy demonstrated evenly distributed chondrocytes within the culture chamber (Figure 1B). Pro-inflammatory stimulation down-regulated COL1A1, COL2A1, ACAN and SOX-9 in monolayer and pellet cultures only; COL10 was down-regulated in monolayer and pellet cultures but up-regulated in the Pregenerate chip. MMP3 and MMP13 were up-regulated in all three culture systems. ADAMTS-5 was down-regulated in the chips only. There was no change in expression of MMP1 in any of the culture systems.

Conclusion

These results demonstrate distinct differences in human chondrocyte responses to pro-inflammatory stimuli in the Pregenerate microfluidic chip cf. traditional culture conditions. Further work is needed to investigate these differences and which system is more synonymous with in vivo behaviour.

abstract fig pregenerate.jpg

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Poster Culture Models

P009 - Development of a Human Synovial Joint-on-a-Chip Model

Presentation Topic
Culture Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Both C. Thompson and M. Knight are involved in the running of the Emulate+Queen Mary Organs-on-Chips centre (centre scientist and centre director respectively) which is partly funded by Emulate inc.
ICRS Award
Cum Laude

Abstract

Purpose

There is an unmet need for novel, disease-modifying pharmaceuticals for the treatment of osteoarthritis (OA). The development of such therapeutics is hampered by a lack of physiologically relevant preclinical models, which contributes to significant attrition in the drug development pipeline. Organ-on-a-chip technology can be utilised to generate new in vitro models with a greater capacity to replicate human physiology in health and disease. Our aim is to develop an organ-on-a-chip model of the human synovial joint.

Methods and Materials

A commercially available, two-channel, microfluidic chip (Chip-S1®, Emulate Inc) was used to develop the joint-on-a-chip model (Figure 1A). Primary human fibroblast-like synoviocytes (FLS) were cultured in the top channel within 10% Matrigel to replicate the intimal synovial lining layer, and primary human chondrocytes were cultured in the bottom channel within 2% agarose to mimic the articular cartilage (Figure 1A). After 24h, cell viability in the chip was assessed by live/dead (calcein AM/ethidium homodimer 1) staining. After 72 hours, cell morphology and cytoskeletal architecture was assessed by actin labelling.

ooac figure 1.png

Results

FLS and chondrocyte viability was maintained at 24h (Figure 1B) and exhibited appropriate cytoskeletal architecture at 72h (Figure 2). Chondrocytes demonstrated a characteristic spherical morphology and were distributed evenly throughout the agarose. FLS were fibroblastic and formed a single layer of cells within the top channel of the chip, over the dividing membrane (Figure 2).

ooac figure 2.png

Conclusion

The work presented here represents the early stages of development of a human synovial joint-on-a-chip and suggests that this model, built upon the Emulate Chip-S1®, is viable. Further validation of the model is currently ongoing. The Emulate system allows for the application of mechanical stimulation in the form of fluid shear and tensile strain and has numerous potential applications. For example, synovial inflammation can be mimicked through the addition of pro-inflammatory cytokines and drug (e.g. steroid) therapeutic efficacy can be screened.

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Poster Culture Models

P010 - The Differentiation of Human Chondrocytes in Scaffold-free 3D Tissue Culture is Independent of the Utilized Serum Type

Presentation Topic
Culture Models
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

In vitro cell culture and tissue engineering techniques often rely on animal sera such as foetal bovine serum (FBS) or on human serum (HS). However, reproducibility of experiments and applicability of the results on in vivo situations is limited. Furthermore, there are ethical concerns (1) with the production of FBS via killing calves in the womb, and (2) the use of blood donations for the production of HS for research. Hence, the aim of this study was to compare the differentiation degree of cartilage-like microtissues cultivated with species specific sera and a chemically defined serum (CDS).

Methods and Materials

Human primary chondrocytes isolated from knee joints were expanded in medium containing HS. Scaffold-free microtissues were generated and cultivated in cell-repellent plates using three different sera: HS, FBS and CDS. After two and four weeks, the macroscopic appearance (reflected-light microscopy) was documented and the size was determined. The differentiation degree was evaluated via histology to visualize typical glycosaminoglycans (Safranin O, Alcian blue) and immunohistochemistry (IH) to detect cartilage-specific markers (collagen type II, proteoglycans, Sox9) and collagen type I on cryosections.

Results

All microtissues had a whitish colour both after two and four weeks cultivation. Cartilage-like microtissues cultivated with HS or FBS were similar in size, whereas those cultivated with CDS were more than 10% bigger. Already after two weeks, cartilage-like microtissues of all tested sera showed an expression of cartilage-specific markers, which increased after four weeks. Collagen type I was always weakly expressed. The expression level of all tested markers was similar regardless of serum type.

Conclusion

This study suggests that the differentiation degree of cartilage-like microtissues in cell-repellent plates is not influenced by the serum type. Hence, CDS can replace species specific sera to reduce ethical concerns and batch-to-batch variations. The applicability of CDS to the expansion of chondrocytes remains to be determined.

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Poster Cartilage Imaging and Functional Testing

P012 - Development of a Novel Quantitative Ultrasound Parameter to Measure Tidemark Remodeling

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
C.D. Hoemann, Ortho RTi, shareholder, Scientific Advisoary Board. All other authors: No significant relationship.

Abstract

Purpose

Traumatic joint injury can initiate osteoarthritis and launch a slow process of creeping mineralization and tidemark advancement through unclear mechanisms. High-frequency ultrasound is a non-destructive approach that can be used to image the cartilage-bone interface. The purpose of this study was to develop a novel quantitative ultrasound (QUS) parameter that reflects alterations in tidemark structure due to changes in mineralization.

Methods and Materials

Osteochondral explants 3mm in diameter were extracted with 8G Jamshidi needles from an adult bovine shoulder (N=1) or intact human knee cartilage (N=3, de-identified arthroplasty surgical waste). Explants were cultured in vitro, fixed and decalcified in EDTA. Specimens were SAM scanned by raster-scanning a 15 MHz transducer (Olympus) at the optimal focal length of 50.8 in a 6x6mm grid at 100 µm steps. A log-compressed envelope signal (dB per mm) in a 1 mm2 area in the center of each explant was produced (MATLAB). The QUS alpha parameter was defined as the slope (dB/mm) between the maximal subchondral signal and 200 µm prior. Differences were evaluated by matched pair design (JMP-Pro, significance set at p˂0.05).

Results

Osteochondral SAM scans produced two prominent signals along the scanning axis at the articular cartilage surface and the tidemark (Fig. 1A), as previously reported by others. We report the novel finding that decalcification altered the echogenic backscatter at the tidemark, with increased echogenicity in subchondral bone (Fig. 1B). Compared to healthy bovine tissue, human OA articular cartilage was thicker, produced more backscatter inside the articular cartilage, showed higher alpha values, and required longer decalcification times to observe changes in alpha.

fig1(1).jpg

Conclusion

A high alpha indicates a rapid spatial increase in echogenicity that is expected for a well-developed and intact mature tidemark. Tidemark advancement produces a hypomineralized tissue suggesting that QUS could be useful for identifying longitudinal changes in the tidemark, in an explant model.

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Poster Cartilage Imaging and Functional Testing

P013 - Viability and Metabolic Changes in Chondrocytes During Prolonged Storage Evaluated Using a Fluorescent Tri-Stain Method

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The Missouri Osteochondral Allograft Preservation System (MOPS) has been shown to extend the period of acceptable cell viability compared to the standard of care (SOC). Metabolic changes and mechanisms by which cells remain viable cannot be evaluated using common viability assessments. This study aimed to compare metabolic changes in chondrocytes after storage in MOPS or SOC conditions using a tri-stain method.

Methods and Materials

Ovine femoral condyles were stored using MOPS (proprietary media, 22-25°C storage) or SOC [Lactated Ringer’s solution, cefazolin (1 g/L), bacitracin (50,000 U/L), 4°C storage]. Cartilage was stained concurrently with Calcein-AM, Ethidium Homodimer-1, and Mitotracker and imaged using a confocal microscope following dissection (fresh control) or after 56 days of storage. Morphological features, including presence of a Mitotracker boundary (Fig. 1B-E) was used to develop a grading system (Fig. 1) ranging from Grade-1, representing highly metabolic and viable cells, to Grade 5, representing dead cells with no metabolic activity. Results were reported as percentage of total cells per grade, with % live calculated by summation of Grades 1 and 2 (no Ethidium Homodimer present). T-tests were performed.icrs_fig1.jpg

Results

1513 cells were graded in 9 samples (Table 1). When compared to SOC, MOPS samples displayed higher percentage of living cells and Grade-2 cells, as well as less Grade-3 and Grade-4 cells. When compared to controls, both 56-day storage groups had significantly lower Grade-1 cells and significantly higher Grade-5 cells. The mechanism causing the Mitotracker boundary (Fig. 1B-E) is unknown with a possible explanation of intracellular organelle transfer due to cell stress signaling.

icrs_table1.jpg

Conclusion

MOPS maintained more viable chondrocytes than SOC after 56 days of storage. The grading system revealed changes in metabolic activity and viability resulting from storage. The three-stain approach and novel grading system allowed categorization beyond the live/dead binary and may contribute to understanding how chondrocytes respond to prolonged storage.

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Poster Cartilage Imaging and Functional Testing

P014 - Establishment of a New Qualitative Evaluation Method for Early Articular Cartilage Injury by MRI Using a 17O-labeled Water as a Water Tracer

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

In the early stages of cartilage damage, development of diagnostic methods focusing on the mechanism of maintaining hydrostatic pressure of cartilage is thoughted to be useful. On the other hand, 17O-labeled water, which is a stable isotope of oxygen, has the advantage of being free from radiation exposure and allergic reactions, and can be detected as the dynamics of water molecules by MRI. The purpose of this study is to evaluate MRI images using 17O-labeld water in a rabbit model.

Methods and Materials

Anterior cruciate ligament transection surgery was performed on 14-weeks-old male Japanese white rabbit. The lower legs were harvested at 4- and 8-weeks postoperatively, and MRI imaging, macroscopic and histological evaluation were performed. Using 3T MRI scanner, T2-weighted images using the 2D-fast spin echo method were performed repeatedly 18 times. 3 scans after the dynamic scanning, 17O-labeled water was manually administered via catheter. Multiple small regions of interest (ROI) were set in the articular cartilage of both condyles referring to the macroscopic or histologically apperance. Concentration of 17O in each phase of each ROI was calculated using the signal value of the T2-weighted image. The time course of concentration of 17O in each ROI was evaluated between the macroscopic and histological grades. All results were statistically compared using one-way ANOVA and significance was accepted with a p value < 0.05.

Results

An increase in novel contrast medium concentration was observed by MRI, consistent with macroscopic and histologically injured areas.
The macroscopic evaluation between the two groups showed that the concentration of 17O increased significantly after Phase 10 compared to the control area. Histologic evaluations also showed that the concentrations of 17O significantly increased in the group of OARSI grading 3 compared with that of other grades.

Conclusion

17O-labeled water could visualize earlier articular cartilage damage, which is difficult to detect by conventional methods.

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Poster Cartilage Imaging and Functional Testing

P015 - Feasibility of Near-Infrared Reflective Spectroscopy to Measure Local Variations in Cartilage Quality: A Human and Animal Cadaveric Study

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

There is a clinical demand for a tool for peri-surgical, non-destructive evaluation of local cartilage quality. Such a tool can be used for evaluation of treatment necessity, determination of (viable) borders of a cartilage defect, and evaluation of repair tissue during second-look surgeries. Therefore, the aim of this study was to assess the feasibility of near-infrared spectroscopy as a tool for non-destructive, minimally-invasive measurement of cartilage quality.

Methods and Materials

A custom-developed 2-mm optical-fibre probe was attached to a 350-1830nm wavelength spectrometer. 450 diffuse reflectance spectra were obtained from 90 cartilage sites on eight fresh-frozen human cadaveric knees. Local glycosaminoglycan, hydroxyproline and water content; cartilage thickness; Young’s modulus (using micro-indentation); T1rho and T2-mapping MRI images; and macroscopic osteoarthritis score were obtained. With 35 spectral features, related to water, lipids and blood, a linear regression model was used to assess the relation to physiological outcome parameters. Moreover, a linear discriminant classification model was used to study the discriminative power between weight-bearing and non-weight-bearing areas. Additionally, in a mini-pig cartilage-defect model, the difference between defect and nearby control areas (40 measurements over 8 defects) was classified directly post-mortem.

Results

The linear models showed the best correlation with osteoarthritis score (R2=0.72), cartilage thickness (R2=0.70), and hydroxyproline content (R2=0.61), and the weakest with Young’s modulus (R2=0.42). Higher correlation to T2 mapping than T1rho (R2=0.55 vs 0.45) was found, suggesting higher sensitivity to matrix organization than concentration. Weight-bearing and non-weight-bearing parts were classified with high accuracy (90.9%). Spectral measurements in- and outside the cartilage defects in the mini-pigs (Fig. 1) could be classified with 100% accuracy.

icrs_fig1.jpg

Conclusion

Good correlations between spectral features and osteoarthritis-related measures were found. Further validation in vivo is needed. The discriminative classification between healthy and damaged cartilage was excellent, suggesting that applications for cartilage defect (repair) evaluation are feasible.

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Poster Cartilage Imaging and Functional Testing

P016 - MicroCT Analysis of Subchondral Bone Reveals Disorganized Architecture after Cartilage Damage

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

There are numerous treatment modalities of the ankle and knee that work to address cartilage damage. The purpose of our study is to determine the extent of damage in the subchondral bone after chondral injuries as it relates to the bony architecture to provide evidence for why certain treatment modalities may fail.

Methods and Materials

Samples were fixed in 10% formalin for 48 h then transferred to 70% ethanol. Quantitative three-dimensional evaluation of the samples was undertaken by μCT using a Viva CT 80 (Scanco, Brüttisellen, Switzerland) at 55 kVp and 145 μA with a resolution of 15.6 μm voxel size. A hydroxyapatite calibration phantom was used to scale values of linear attenuation for the calcified tissues to bone density values (mg/cm3). Calcified tissues were segmented using a thresholding procedure in which bone was defined by a threshold above 500mg HA/cm3.

Results

Of the four diseased samples, the average relative bone volume (%) was 11.86. Comparatively, the four allograft controls contained a relative bone volume (%) of 16.54. Two diseased samples did not have allograft controls for direct comparison.

figure 1 microct.png

figure 2 microct.png

Conclusion

Damaged subchondral bone is a known source of continued pain, declining results, requirement for additional procedures, and OA progression after injury. This study is the first of its kind to utilize microCT to analyze damaged osteochondral samples in an attempt to quantify the damage.

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Poster Cartilage Imaging and Functional Testing

P017 - The relation between the Biochemical Composition of Knee articular Cartilage and Quantitative MRI: A Systematic Review and Meta-analysis

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Non-invasive detection of early stages of osteoarthritis (OA) is required to enable early treatment and monitoring of interventions. The earliest signs of OA include proteoglycan-content decrease and disruption of collagen network integrity. The aim of this study was to establish the relations between quantitative magnetic resonance imaging (MRI) and biochemical content and collagen organization in knee articular cartilage, measured by a biochemical assay or polarized light microscopy (PLM).

Methods and Materials

A preregistered systematic literature review was performed using the databases PubMed and Embase. Papers were included if a quantified correlation was described between quantitative MRI measures and either a biochemical assay measurement of proteoglycan/collagen concentration, or PLM measures for collagen organization. The extracted correlations were pooled using a random effects model, if the heterogeneity allowed it.

Results

21 papers were identified. The strongest pooled correlation was found for delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) versus proteoglycan concentration (r=0.59, fig. 1). T1ρ relaxation times were inversely correlated to proteoglycan concentration (r=-0.54). A weak correlation between T2 relaxation times and proteoglycans was found (r=-0.38). No correlation between T2 relaxation time and collagen concentration was found (r=-0.02). A heterogeneous set of correlations between T2 relaxation times and PLM were identified, including strong correlations to anisotropy.

fig_3_icrs.jpg

Conclusion

dGEMRIC showed the strongest correlation to proteoglycan concentration. The required injection of contrast agent is however a disadvantage; the T1ρ sequence was found as the non-invasive alternative. Remarkably, no correlation was found between T2 relaxation times and collagen concentration. T2 relaxation times is related to organization, rather than concentration of collagen fibers.

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Poster Cartilage Imaging and Functional Testing

P018 - 3D-Model Analysis of Tissue Engineering Construct for Articular Cartilage Restoration - A Pre-Clinical Study

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The chondral lesion and osteoarthritis are conditions associated with an economic burden, since if left untreated may cause changes in the biomechanics of the joint and result in several injuries considered highly disabling to the individual. Mesenchymal Stem Cells (MSCs) have the immunomodulatory capacity and paracrine signaling that are useful for tissue bioengineering to treat bone and cartilage injuries. MRI is a non-invasive method for morphologic and quantitative evaluations. This study aims to develop an innovative technology through a tridimensional (3D) model based on MRI to describe cartilage restoration by tissue engineering and cell therapy treatments in a Good Manufacturing Practice (GMP) translational large animal model

Methods and Materials

A controlled experimental study in fourteen Brazilian miniature pigs was performed, using scaffold-free Tissue Engineering Construct (TEC) from dental pulp and synovial MSCs with 6 months follow-up. To compare the cartilage with and without TEC, MRI were collected from both knees using two sequences, followed by the 3D reconstruction using the software 3D Slicer.

Results

The tissue repair was morphologically assessed from MRI and the 3D reconstruction of the images demonstrated the volume difference of the cartilage with and without TEC.

Conclusion

The 3D reconstruction of the knee cartilage was performed based on MRI stablished protocol and was capable to assess the quality and quantity of the cartilage, demonstrating its high clinical relevance.

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Poster Cartilage Imaging and Functional Testing

P019 - Variants in LRP1 Links Triradiate Chondrocytes Differentiation are Responsible for DDH in Humans and Mice

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Developmental dysplasia of the hip (DDH) is one of the most common congenital malformations, and it exhibits autosomal dominant inheritance by unknown mechanisms. The pathological mechanisms of DDH are poorly understood previously, which hampers the development of diagnostic tools and treatments.

Methods and Materials

We conducted whole-exome sequencing and identified 10 distinct variants including missense and splice site mutations of the LRP1 (low density lipoprotein receptor-related protein 1) gene in 2 consanguineous families and 7 unrelated DDH cases from a cohort of 8 consanguineous families and another cohort of 68 unrelated cases DDH-affected Han Chinese child, approximately 13% of the individuals carry novel/rare variants in LRP1. All of the patients harboring LRP1 variants presented a typical DDH phenotype and had complete dislocation of the hips.

We establish a mouse line with Lrp1 gene variants knock-in (KI) via CRISPR-Cas9 System. Micro-CT reconstruction of the acetabular and femoral head of each mice were conducted. Acetabular fossa and femur were rinsed overnight with clean water for hisological staining. The isolation and culture of mice BMSCs from the tibias and femurs of 4-wk-old WT and Lrp1+/- C57/B6 mice were performed. Pellet generate from the BMSCs. Expression level of Lrp1 was specifically knock down in ATDC5 cells using concentrated lentiviruses expressed control-sgRNA or Lrp1-sgRNA.

Results

The timing of triradiate cartilage had been brought forward one or two weeks early in Lrp1R1783W-mutated and Lrp1+/- mice, which stop the acetabulum from growing deeper and wider. Lack of Lrp1 caused a significant decreased chondrogenic ability in vitro. Inhibited autophagy levels and significant up-regulated β-catenin during the chondrogenic induction of mice BMSCs and ADTC5 cell line were detected. Furthermore, we succeeded in rescuing the expression of Col2a1 and Sox9 by treat with 10 or 20 mM PNU in vitro.

Conclusion

Our genetic and protein interaction evidence could open avenues for future studies of DDH.

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Poster Clinical Outcome

P020 - Primary Segmental Labral Reconstruction for Irreparable Labral Tears in the Hip: Minimum Five-Year Outcomes

Presentation Topic
Clinical Outcome
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Financial interests: Amplitude, Arthrex, ATI, Breg, DJO Global, Kauffman Foundation, MAKO Surgical, Medacta, Medwest, Orthomerica, Pacira Pharmaceuticals, Stryker Affiliations: American Hip Institute, Hinsdale Orthopaedics, North Shore Surgical Suites,

Abstract

Purpose

1) To evaluate minimum 5-year patient-reported outcome scores (PROs) in patients who underwent primary SLR with hamstring graft, in the setting of femoroacetabular impingement syndrome (FAIS) and irreparable labral tears, and 2) to compare the outcomes of hamstring autograft vs. allograft in a subanalysis using propensity-matched groups.

Methods and Materials

Prospectively collected data were retrospectively reviewed for patients who underwent primary hip arthroscopy from September 2010 to November 2015. Patients were included if they underwent SLR using hamstring autograft or allograft and had preoperative and minimum 5-year PROs. Exclusion criteria were previous ipsilateral hip surgery/conditions, dysplasia, or Tönnis grade > 1. Patients with autograft SLR were propensity-matched 1:1 based on age, gender, and body mass index (BMI) to patients who underwent SLR using hamstring allograft. The minimal clinically important difference (MCID), and patient acceptable symptomatic state (PASS) were calculated.

Results

48 hips were eligible to be included in this study, and 41 hips (85.4%) had minimum 5-year follow-up reporting significant improvement in all PROs. Fifteen of the 41 included patients underwent a SLR with a hamstring autograft and were matched to 15 patients with labral reconstruction using allograft hamstring. Groups were similar for gender (P >.999), age (P = .775), and BMI (P = .486). The average follow-up time was 80.8 ± 25.5 and 66.1 ± 8.3 months (P = .223) for the autograft and the allograft groups, respectively. Baseline PROs, preoperative radiographic measurements, surgical findings and intra-operative procedures were similar. The groups achieved significant and comparable improvement for all PROs (P < .0001), satisfaction (P = .187), and rate of achieving the MCID and PASS.

Conclusion

At minimum 5-year follow-up, patients who underwent primary arthroscopic SLR, in the context of FAIS and irreparable labra, reported significant improvement and comparable postoperative scores for PROs, patient satisfaction, MCID, and PASS using either autograft or allograft hamstrings.

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Poster Cartilage Imaging and Functional Testing

P021 - Incidence of (Osteo)Chondral Lesions Concomitant to Chronic Lateral Ankle Instability: Systematic Review and Meta-analysis

Presentation Topic
Cartilage Imaging and Functional Testing
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To determine the incidence of (osteo)chondral lesions ((O)CLs) in patients with chronic lateral ankle instability (CLAI).

Methods and Materials

A literature search was conducted in the PubMed (MEDLINE), EMBASE (Ovid), and the Cochrane Library databases for articles published from January 2000 until December 2020. Two authors independently screened the search results and conducted the quality assessment using the MINORS criteria. Clinical studies that reported findings on (O)CLs of the ankle as per preoperative or intraoperative diagnostic measures in patients with CLAI (> 6 months of symptoms) were included. Chondral and osteochondral lesions were analyzed altogether for the primary outcome, namely, the incidence of (O)CLs in ankles with CLAI. Additionally, a subgroup analysis for the incidence of (O)CLs located on the talus. Secondary outcomes included the study-, patient, and lesion characteristics. Lesions characteristics included lesion localization and chondral- or osteochondral involvement. A random effects model with 95% confidence intervals (95% CI) was used to analyze the primary outcome and subgroup analysis. Secondary outcomes were pooled using a simplified pooling method.

Results

afbeelding1.png12 studies with a total of 2145 patients with 2170 ankles with CLAI were included. The overall pooled incidence of (O)CLs in ankles with CLAI was 32.2% (95% CI 22.7 – 41.7). The pooled incidence of talar (O)CLs was 26.5% (95% CI 19.0 – 34.0). Overall the most common location of OCLs in patients with CLAI is the talus with 85%, of which 68% of (O)CLs are located on the medial talus and 32% are located laterally. 43% of lesions were chondral lesions and 57% of lesions were osteochondral in nature.

Conclusion

(O)CLs were found in up to 32% of ankles with CLAI. Furthermore, most lesions are located on the medial talar dome. These findings will aid physicians in the early recognition and treatment of ankle (O)CLs in the context of CLAI.

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Poster Extracellular Matrix

P023 - A Quantitative Collagen Fibril Population Analyses of 39 Jone’s Free ACL Autografts vs Time

Presentation Topic
Extracellular Matrix
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Why do so many Anterior Cruciate Ligament Reconstructions (ACLR’) fail/rupture in the young athlete ?

In my country one Australian Rules Football (ARF) player had 5 ACLR’s in 5 years & ALL failed !

Uribe et al. CORR 325:91-99,1996 and others have noted from 3-22% recurrent patholaxity.

Also recently L.J.Salmon et al AJSM 2018;46(3):531 has reported recently the high graft overt rupture rate of ACLR in athletes < 20 yrs old of ~ 36% !!

In (2020) in Carlsbad, Bert Mandelbaum, an experienced ACLR surgeon displayed a failed ACLR in an NFL player.

Methods and Materials

Biopsies of human ACL autografts from 6 months implantation to 10 years post-implantation were obtained in patients with meniscal and or articular cartilage lesions.

Quantitative ultrastructural studies of collagen fibril populations using specific software were performed on human 39 ACL autografts using the PT, Hamstrings, IT band and were compared to the normal ACL and PT.

Results

The outstanding feature was the absence of large diameter collagen fibrils >100nm after 6 months post-surgery and the predominance of small diameter fibrils <100nm diameter which were not arranged in normal fasciculi. The ACL graft itself was usually lax, soft and easily probed compared to the robust and firm nature of the normal ACL when probed and defined as two distinct bundles.

Conclusion

All the ACL autografts except at 6 weeks contained predominantly small fibrils < 100nm diameter.

Large fibrils > 100nm were not replaced at 10 years post-implantation.

This is a ‘de-ligamentization’ of these autografts.

This tissue if of poor tensile quality and is doomed to failure either by creep elongation or complete grade 3 overt failure.

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Poster Histology

P024 - Macroscopic Assessment of Articular Cartilage Quality Correlates with Histological Assessment of Subchondral Bone Health

Presentation Topic
Histology
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

In the human knee, the articular cartilage (AC) and subchondral bone (SB) form a biomechanically and biochemically functional osteochondral unit. Macroscopic cartilage assessment by arthroscopy is commonly used to determine AC lesion severity prior to surgery. We previously reported that the health of the SB could influence outcomes following cell-based therapy for AC repair, but macroscopic assessment gives no indication of SB health. Our aim was to assess correlation between the macroscopic and histological grading systems.

Methods and Materials

Osteochondral tissue samples were collected from patients undergoing total knee replacement surgery (TKR). AC was graded macroscopically using the ICRS Cartilage Lesion Classification System (grade 0 (normal) – grade 4 (severely abnormal)). Two osteochondral fragments, one with the lowest grade (most normal) and one with the highest grade (most abnormal) cartilage, were obtained for each TKR patient. Sections were stained with haematoxylin & eosin and safranin O/fast green before histological assessment. AC was graded using the OARSI OA Cartilage Histopathology Assessment System (grade 0 (normal) – grade 6 (deformation)). SB was graded using the SB Histological Grading System (grade 0 (early OA) – grade 3 (late-stage OA)). The relationship between scores was assessed using Kendall’s rank correlation coefficient (Kendall’s tau).

Results

Sixteen TKR patients (6 female, 10 male; 68.2±6.7SD years-old), were included, resulting in the generation of 32 paired osteochondral fragments with the most normal and most abnormal cartilage for each patient. The ICRS score demonstrated moderate-to-strong correlation with both the AC and SB histological scores (Table 1, Figure 1). The AC and SB histological scores were also strongly correlated (Table 1).

icrs correlation.png

icrsxsb.png

Conclusion

Our results suggest that macroscopic cartilage assessment, using the ICRS scoring system, may give an indication of histologically assessed AC and SB health. This study provides further evidence for the close association between the AC and SB in patients with established knee osteoarthritis.

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Poster Histology

P025 - Severity of Synovitis and Macrophage Phenotypes in Knee Cartilage Defect and Osteoarthritis Cohorts

Presentation Topic
Histology
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Growing evidence suggests that the synovium is important in the pathogenesis of osteoarthritis (OA). Synovial macrophages demonstrate considerable plasticity in mediating joint inflammation and OA progression. In this study we examined the synovia from patients with either cartilage defects or end-stage OA in the knee.

Methods and Materials

Synovial tissues were obtained from patients undergoing cell therapy to treat cartilage defects (at time of cell implantation, ~3 weeks post cell harvest) or arthroplasty surgery. Haematoxylin and eosin-stained sections of synovial tissue were assessed for synovitis using a histological scoring system (Krenn score). Pan-macrophage (CD68) and polarisation markers (CD86:M1 and CD206:M2) were assessed by immunohistochemical staining and subsequent semi-quantitative analysis.

Results

Samples of synovium were collected during surgery from 15 cell therapy (6 female, 9 male; 39.2±2.18SEM years) and 15 arthroplasty patients (8 female, 7 male; 67.3±2.80SEM years). Mean synovitis scores were significantly higher in the cell therapy group cf. the arthroplasty group (Table 1). The mean intensity of CD68, CD86 and CD206 immunostaining was also significantly higher in the cell therapy group cf. the arthroplasty group. The ratio of CD86 to CD206 was significantly higher in the cartilage injury synovia cf. OA synovia. Linear regression analysis of the full dataset indicated that CD86 intensity was a significant predictor of synovitis severity (cor.coeff.=0.052, p=0.016, 95% CI [0.036-0.234]).

macrophage markers.png

Conclusion

Increased synovitis, abundance of macrophages (CD68, CD86 and CD206 positive) and increased CD86:CD206 staining ratio (indicative of M1 favoured polarisation) in synovia from patients undergoing cell therapy for cartilage defects is suggestive of a macrophage-mediated, pro-inflammatory immune response. Whether this response relates to the harvest stage of cell therapy or cartilage defect pathology warrants further investigation. Conversely, the reduced abundance of macrophages in arthroplasty synovia suggests a reduced ability of the synovium to mount an immune response at the end-stage of OA, indicative of organ-level failure within the joint.

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Poster Histology

P026 - Statistical Image Analysis and Escort Histograms in Characterization of Articular Cartilage Repair in a Skeleton Animal Model

Presentation Topic
Histology
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Statistical image analysis of an ensemble of digital images of histological samples is performed as an auxiliary investigation a result of the recently proposed method of articular cartilage repair utilizing growth plate chondrocytes in a skeleton animal model.

Methods and Materials

A fixed–shift model of maximal likelihood estimates of image histograms applied for monochromatic (grayscale) images or their RGB components confirms the statistically significant effect of the previously proposed medical treatment. The type of staining used to prepare images of histological samples is related to the visibility of the effectiveness of medical treatment.

Results

Hellinger distance of escort distributions for maximal likelihood estimates of image histograms of medically treated and control samples is investigated to identify grayscale (or RGB) intensities responsible for statistically significant difference of the estimates. A difference of Shannon entropy quantifying informational content of the histograms allows one to identify staining and image colors which are most suitable to visualize cluster formation typical for articular cartilage repair processes.

Conclusion

We conclude that the presented analysis causes us to believe that statistical image comparison can serve as a valuable tool for an auxiliary investigation of not–to–large sets of medical images. We claim that using statistical image analysis not only supports standard ‘human– based’ methods of selection of image parameters (such as color) or histological samples (such as applied staining) to represent and visualize the effectiveness of medical treatment but also can lead to new results with direct medical application and value.

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Poster New Cartilage Technology

P027 - Changes in the Avascular Area of the Meniscus Using Mesenchymal Stem Cells and Growth Plate Chondrocytes in a Pig Model

Presentation Topic
New Cartilage Technology
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The aim of the study was to evaluate autologous growth plate chondrocytes’ impact on the healing process of a damaged meniscus in the avascular zone based on a growing animal model.

Methods and Materials

The study group consisted of 10 pigs at about three months of age. From each animal, chondrocytes from the iliac growth plate and from concentrated bone marrow were taken. Knee joints were divided into right (R) and left (L). The medial meniscus of the R knee joint was treated with a hyaluronic acid based scaffold incubated with bone marrow cells from marrow aspirates (nCHON). The medial meniscus of the L knee joint was treated with a hyaluronic acid-based scaffold incubated with bone marrow cells from marrow aspirates supplemented with immature chondrocytes isolated from growth plates (wCHON). The meniscus was damaged in the avascular zone in both knee joints. Followingly, the damaged part of the meniscus was filled with a scaffold with cells from the concentrated bone marrow and from growth plate chondrocytes. In the control group, a scaffold with concentrated bone marrow cells was used. After three months the animals were euthanized and preparations (microscopic slides) were made from the meniscus’ damaged part.

Results

A qualitative and quantitative analysis have been prepared. The wCHON group in comparison with the nCHON group showed a statistically significantly higher number of fusiform cells on the surface of the graft as well as better healing of the graft. In addition, the degree of vascularisation was higher in specimens from the wCHON group than in the nCHON group.

Conclusion

The results of our research on immature pig knees revealed that mesenchymal stem cell and growth plate chondrocytes could be treated as the cell source for meniscus reconstruction, and growth plate chondrocytes enhance healing processes in the avascular zone of the injured meniscus.

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Poster New Cartilage Technology

P028 - Bio-3D printed Scaffold-free Cartilage Construct for larger Chondral Defects.

Presentation Topic
New Cartilage Technology
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
K. Nakayama, shareholder, Cyfuse Biomedical K K, D. Murata, A. Nakamura, M. Ikeya, J. Toguchida, no significant relationships

Abstract

Purpose

End-stage treatment for lager defects, Total Knee Replacement(TKR), demonstrates significant clinical improvement however, due to risk of revision surgery is not preferable for younger patients.Finding new methods for partial or complete resurfacing of synovial joints remains an important challenge. Tissue engineering using scaffold-based technology, although promising alternative approach for repair, is subject to few limitations, such as poor cytocompatibility and degradation associated with toxicity. For that reason, we attempt to engineer a totally scaffold-free functional cartilage construct using a Bio-3D printer based on Kenzan technology.

Methods and Materials

As a material, we used iPSCs derived neural crest cells (NCC) well known for its potential to undergo chondrogenesis through mesenchymal stem cell differentiation. To engineer the tissue, using Bio-3D printer, iNSMSCs spheroids formed in the chondrogenesis induction medium, were automatically placed by the nozzle in the desired position on the Kenzan which is an array of the fine needles. To evaluate the most optimal time for printing, constructs assembled with spheroid from 3 points of induction were analyzed. Biochemical and mechanical analysis of constructs cultured for different time periods were conducted for maturation time optimization. Geometric-dependent shape tissues were printed using various Kenzans.

Results

By optimizing time of fabrication during chondrogenic induction we were able to assembly highly unified, shape-sustainable, cartilaginous construct in size up to 6cm2 with individually-specific topography. Maturation time optimization revealed that following 3 weeks after printing facilitates self-organization of cells, improving mechanical strength and tissue function. Compression modulus reached a range for native cartilage of 0.88MPa in 5th week of maturation.

Conclusion

Herein, we report engineering functional, scaffold-free constructs which may be sufficient for repair of larger chondral defects by successfully combining iPS cells and Kenzan technology using Bio-3D printer.

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Poster Others

P029 - Role of Chemokine CCR7 in the Repair Process after Physeal Injury in Mice

Presentation Topic
Others
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To test hypothsis that chemokine CCR7 would play crucial roles in physeal cartilage regeneration, we investigated the role of CCR7 in the repair process after physeal injury in mice.

Methods and Materials

Growth plate (GP) injury was made in the left proximal tibial GP in 3-week-old C57BL/6 mice (WT) and CCR7 knockout mice (KO) . Proximal tibial GP was entirely pierced with a 25-G needle. Right tibial GPs were sham operated with skin incision only. 3 and 5 weeks postoperatively, length of tibiae was measured macroscopically and height of proximal tibial GP were measured by micro-CT. The tibia shortening ratio (drop-ratio) was defined as percentage that the tibial length difference between sham operated and operated tibia divided by the length of sham operated tibia. Growth plate height ratio was defined as the growth plate length of the operated tibia divided by that of the sham operated tibia. Bone volume of the physeal bridge at the injury site and bone mineral density (BMD) of the subchondral area were measured using micro-CT. All results were statistically compared using unpaired t-tests to evaluate differences between pairs of groups. Significance was accepted with a p value < 0.05.

Results

3 and 5 weeks postoperatively, drop ratio of tibial length and bone volume of physeal bridge in KO mice was significantly lower than those in WT mice (Fig. 1, 2). Growth plate height ratio in KO mice was significantly higher than those in WT mice at both 3 and 5 weeks (Fig. 2). In contrast, BMD of subchondral area were almost same between KO and WT mice, and between sham and operated tibia at either 3 or 5 weeks.

fig1.jpg

fig2.jpg

Conclusion

Depletion of CCR7 in mice inhibited physeal bridge formation and ameliorated growth imbalance after physeal injury. These results suggested that CCR7 might have important roles in physeal bridge formation.

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Poster Others

P030 - The Injured Enthesis Heals by a Novel Mechanism, Whereby ECM Secretion by Resident Cells Forms an Acellular Scar

Presentation Topic
Others
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Wound healing is a well-orchestrated process that restores the structure and function of an injured tissue through the involvement of the immune and vascular systems. Injuries to the enthesis, a transitional tissue that connects between tendon and bone, often result in scar formation and loss of mechanical properties, thereby severely affecting function and life quality. Nevertheless, a detailed investigation of the enthesis healing process has not been conducted.

Methods and Materials

To explore the healing process of the enthesis, we established a partial injury model in the Achilles enthesis of neonatal mice. Following an injury, sequential histological, molecular and behavioral assays were conducted, including in situ HCR, electron microscopy, gait analysis and qPCR.

Results

Shortly after injury, we observed an ECM plug within the lesion. The plug was composed of collagen type I and type II, secreted locally by resident enthesis cells, forming a permanent hypocellular scar. Classical healing attributes, such as the presence of inflammatory cells and angiogenesis, were not observed. Differential spatial distribution of markers of ER stress, autophagy and cell death was observed in the different zones of the enthesis. Eventually, gait capacities were restored, while no regeneration was observed.

32586_figure_39468_ron_vinestock_eli_zelzer_v9.jpg

Conclusion

These findings offer a novel healing mechanism, whereby local ECM secretion by resident cells forms an acellular plug in the absence of inflammation markers. This insight into the healing mechanism of a complex transitional tissue may promote new therapeutic strategies for enthesis injuries.

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Poster Others

P031 - Lower Limb Realignment Osteotomies Around the Knee: A Dutch Survey

Presentation Topic
Others
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Realignment osteotomies around the knee are a proven surgical treatment for unicompartmental knee osteoarthritis (OA). This treatment is gaining popularity amongst Dutch orthopaedic surgeons. However, exact numbers and used standards in clinical practice concerning osteotomies are yet unknown due to the absence of a national registry. Nationwide insights and standardisation of osteotomy care could prevent outliers and thereby improve this treatment. The aim of this study was to investigate the national statistics of performed osteotomies, utilized clinical workups, surgical techniques, and post-operative rehabilitation standards in the Netherlands.

Methods and Materials

Dutch orthopaedic surgeons, all members of the Dutch Knee Society, received a web-based survey between January and March 2021. This electronic survey contained 36 questions, subdivided into general surgeon-related information, number of performed osteotomies, the inclusion of patients, clinical workup, surgical techniques, and post-operative management.

Results

The response rate was 27% (60 of 222 members), who perform realignment osteotomies around the knee. All the 60 responders (100%) perform high tibial osteotomies and 63.3% additionally perform distal femoral osteotomies, while 30% perform double-level osteotomies. Discrepancies in surgical standards were reported in inclusion criteria (Figure 1), clinical workup (Figure 2), surgical techniques, and post-operative strategies.

afbeelding1.pngafbeelding2.png

Conclusion

Clinical standards applied by Dutch orthopaedic surgeons concerning realignment osteotomies in the lower limb have noticeable discrepancies. A nationwide registry for osteotomies would be useful for the overall standardisation and more insight regarding alignment osteotomies, including outcome.

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Poster Others

P032 - Tendon Tissue Repair Using Alginate-cell Cross-linked Gel

Presentation Topic
Others
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
This study is supported in part by Mochida Pharmaceutical Co, Ltd, for material preparations and research funding.

Abstract

Purpose

Tendons are mechanosensitive tissues, and the complex interactions among cells, extracellular matrix, and mechanical loading maintain their homeostasis. Mechanical stress is one of the important factors in musculoskeletal disease and known to develop tissue repair. However, the cell transplantation method has never been developed under mechanical stress that is appropriate for the transplanted cells. The proper mechanical stress to transplanted cells would enhance tendon repair. Thus, we investigated the repair effect of the injured tendon using alginate-cell cross-linked gels, which can transmit mechanical stress to cells by direct cells interaction via alginate gels.

Methods and Materials

The cell cross-linked gels were prepared to suspend the azide-modified bone marrow mesenchymal stromal cells (MSCs) with dibenzocyclooctyne modified branched alginic acid (bAlg-DBCO) solution. Alginate gels with MSCs were prepared in the same way using non azide-modified MSCs. Lewis rats were anesthetized, and the mid-substance in the Achilles tendons was excised and treated with NS (Control group), alginate gels alone (AL group), alginate gels with MSCs (MSCs group), and cell cross-linked gels (Crosslinked group). Rats were sacrificed at 2 or 4 weeks postoperatively. The Achilles tendons were evaluated by Modified Watkins scores for general histologic assessment. For mechanical evaluation, ultimate load to failure and stiffness were calculated. Data were presented as the mean ± SD. Significant differences among groups were assessed using one-way analysis of variance (α = 0.05).

Results

At 4 weeks, The modified Watkins scores of Crosslinked group was significantly greater than other groups (Fig. 1). For biomechanical assessment, at 4 weeks, the physical property of Crosslinked group was superior to other groups (Fig. 2).

icrs fig1.jpgicrs fig2.jpg

Conclusion

In rats Achilles tendon defects model, we demonstrated that alginate-cell cross-linked gel developed repair of injured tendon. To interact cells directly using alginate gels, mechanical stress might be transmitted to cells. Eventually, cross-linked gels developed superior oriented parallel tendon tissue.

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Poster Others

P033 - Microstructural Differences Between the Osteochondral Units of Terrestrial and Aquatic Mammals

Presentation Topic
Others
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The osteochondral unit is the pivotal element of the mammalian joint, with a fundamental clinical relevance. It is known that in terrestrial mammals, that the biochemical components of the tissues of the osteochondral unit are strongly preserved across a wide range of species. There is, however, very limited knowledge of specific adaptations of the architecture of the cartilage extracellular matrix in aquatic mammals.

The aim of this study was, therefore, to investigate if and how the structure of both the cartilage and the bone component of the osteochondral unit differs between mammals living on land or in water.

Methods and Materials

To investigate this we analyzed the microstructural composition and architectural features of the osteochondral units from the humeral head of six aquatic and nine terrestrial mammalian species. Osteochondral tissue samples were harvested post-mortem from the weight bearing central area of the humeral head. Histological assesment was performed, and included saf-O staining and polarized light microscopy to visualize the orientation of the collagen fibers. The mechanical properties were assessed by uniaxial unconfined compression and Micro Computed Tomography (micro-CT) was performed.

Results

schermafbeelding 2021-10-14 om 18.00.22.png

Aquatic mammals feature cartilage with essentially random collagen fiber configuration, lacking the depth-dependent, arcade-like organization characteristic of terrestrial mammalian species. They have a less stiff articular cartilage at equilibrium with a significantly lower peak modulus, and at the osteochondral interface do not have a calcified cartilage layer, displaying only a thin, highly porous subchondral bone plate. Moreover, patches of cartilage tissue are present throughout the subchondral bone.

Conclusion

This totally different constitution of the osteochondral unit in aquatic mammals reflects that accommodation of loading is the primordial function of the osteochondral unit. Recognizing the crucial importance of this microarchitecture-function relationship is pivotal for the development of durable functional regenerative approaches for treatment of joint damage.

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Poster Others

P035 - Agrin Induces Long-Term Osteochondral Regeneration by Supporting Repair Morphogenesis

Abstract

Purpose

Cartilage breakdown is a feature of osteoarthritis, a leading cause of chronic disability, costing 1.5-2% of the GDP in western countries. There is currently no medicine that halts or reverses cartilage breakdown, resulting in joint instability and pain, therefore this is a priority in medicine. Our previous research indicated that Agrin is a potent chondrogenic factor and is able to enhance cartilage matrix formation. Here we investigate the therapeutic use of Agrin for osteochondral defect repair.

Methods and Materials

Surgery was performed on skeletally mature mice (wildtype and Gdf5-Cre;Tom reporter mice) and sheep to create critical-sized osteochondral defects; animals were treated with collagen gel supplemented with PBS or collagen gel supplemented with Agrin. In vitro: WNT and CREB reporter assays, chondrogenic assays, transfection, siRNA, qPCR, western blotting & immunocytochemistry. Ex-vivo: histology, microCT and immunohistochemistry.

Results

A single intra-articular administration of Agrin induced long-lasting regeneration of critical-size osteochondral defects in mice, with restoration of tissue architecture and bone-cartilage interface. Agrin attracted joint resident progenitor cells to the site of injury and, through simultaneous activation of CREB and suppression of canonical WNT signalling downstream of β-catenin, induced expression of the chondrogenic stem cell marker GDF5 and differentiation into stable articular chondrocytes, forming stable articular cartilage. In sheep, the Agrin-containing collagen gel resulted in long-lasting regeneration of bone and cartilage, which promoted increased ambulatory activity.

Conclusion

Agrin induces long-term osteochondral regeneration by supporting repair morphogenesis . No ectopic cartilage formation was observed after intra-articular delivery despite the chondrogenic capacity of Agrin. The capacity of Agrin to preserve the architecture of the native tissue is distinct and of important translational relevance. Our findings support the therapeutic use of Agrin for joint surface regeneration.

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Poster Biomarkers

P038 - Dynamic Biomechanical Markers Examination in the Management of Knee Patients: Literature Review Update on the Knee Kinesiography Exam

Presentation Topic
Biomarkers
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
N.Hagemeister, Emovi Inc., Grant Research Support J.Zeni, Arthritis Care and Research, Editorial or governing board, Emovi Inc., Consultancy Paid A.Cagnin, Emovi Inc., Employee P.Ranger, Bioventus, Consultancy, Sanofi-Aventis, Consultancy, Smith & Nephew,

Abstract

Purpose

Although a clinical examination and X-ray imaging are adequate to diagnose knee osteoarthritis (OA), there is a well-documented discordance between radiographic severity and symptoms. Literature highlights the clinical gap for clinicians to access validated tools to help them better understand dynamic knee dysfunction and mechanical risk factors for disease progression. As well as support them develop and monitor appropriate treatment plans and in their decision process to refer patient for a surgical consultation. The knee kinesiography exam, which assesses and quantifies knee joint dysfunction in the sagittal, frontal, and transverse planes could help fill this clinical gap (Figure 1).

figure 1 kneekg system.png

Methods and Materials

A comprehensive review on the use of the knee kinesiography exam was conducted to update a technical literature review from 2012 within MEDLINE and RESEARCHGATE databases.

Results

Summary of the review’s findings is presented in Table 1. Results showed that biomechanical dysfunctions assessed through a knee kinesiography exam are associated with patients’ symptomatology and function in a greater extent than OA radiographic severity. Furthermore, a personalized conservative approach based on dynamic biomechanical markers demonstrated significant improvements in terms of patients’ clinical outcomes, satisfaction, treatment adherence, and biomechanical dysfunctions (i.e., correction of varus thrust, dynamic flexion contracture). Several studies also highlighted the added value of a knee kinesiography exam in the management of TKA patients by documenting appropriateness for orthopedic consultation, monitoring function, and allowing a better understanding of residual pain post-TKA. Knee kinesiography is also used as a functional outcomes measure to assess the impact of surgery (arthroplasty, sport medicine) in clinical studies.

summary of the review’s findings in studies which used the knee kinesiography exam in the past 10 years.png

Conclusion

This review illustrates how a knee kinesiography exam provides actionable data on knee joint function to successfully improve the understanding of biomechanical dysfunctions. Results highlight the value of this exam for clinicians to personalize and monitor treatments (conservative and surgical) which showed to lead to improved clinical outcomes.

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Poster Biomarkers

P039 - Association Between Osteoarthritis-related Serum Biomarkers over 11 Years and Knee MRI-biomarkers in Middle-aged Adults

Presentation Topic
Biomarkers
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

There is a lack of data on osteoarthritis (OA)-related serum biomarkers' (cartilage oligomeric matrix protein (COMP), matrix metalloproteinase (MMP)-3, and hyaluronan (HA)) association with MRI-markers in the middle-aged general population. Therefore, our aim was to investigate the associations between OA-related biomarkers and MRI-markers in middle-aged adults followed up over 10-13 years.

Methods and Materials

Blood samples were collected during the Childhood Determinants of Adult Health (CDAH)-1 study at baseline (year: 2004-06, age: 26–36 years) and 10-13 year follow-up (CDAH-3; year: 2014–2019, age: 36–49 years). Serum samples from baseline (n=156) and follow-up (n= 167) were analyzed for three OA-related biomarkers – COMP, MMP-3, and HA– using non-isotopic ELISA. Knee MRI scans were obtained during the CDAH-knee study (year: 2008-10, age: 30-40 years, n=313), and were assessed for cartilage volume, cartilage thickness, subchondral bone area, cartilage defects, and bone marrow lesions (BML). Univariable and multivariable (adjusted for age, sex, and BMI) linear regression and logistic regression were used to describe the association of biomarker at CDAH-1 and MRI-biomarkers at CDAH-knee; Tobit regression was used to describe the association of MRI-biomarkers at CDAH-knee and biomarkers at CDAH-3.

Results

In the multivariable model a significant negative association of COMP with medial femorotibial compartment cartilage thickness (-0.010 (-0.019, -0.000);p=0.045), and MMP-3 with patellar cartilage thickness (-9.075 (-16.344, -1.807);p=0.015) and total bone area (-0.047 (-0.086, -0.007);p=0.020) was found.

In the multivariable model a significant negative association of total cartilage volume (-0.0005 (-0.0008, -0.0002);p=0.001) and total cartilage thickness (-0.628 (-1.143, -0.114);p=0.017) with MMP-3, and total bone area with COMP (-0.270 (-0.474, -0.006);p=0.010) was observed.

Conclusion

COMP and MMP-3 levels were negatively associated with knee cartilage thickness assessed 4-years later. Knee cartilage thickness and volume were negatively associated with COMP and MMP-3 levels assessed 6-9 years later. These results suggest that OA-related biomarkers may predict future MRI-markers in middle-aged adults.

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Poster Biomaterials and Scaffolds

P040 - Influence of Type I Collagen-Based Meniscus Scaffold and PRP on Adipose-Derived Stem Cells Differentiation Under Static Culture Condition

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The overall goal is to develop a type I collagen-based meniscus regeneration implant applying tissue engineering strategy. In the current study, platelet-rich plasma (PRP) was used to induce chondrogenic differentiation of human adipose-derived mesenchymal stem cells (hASC) in a novel type I collagen-based scaffold.

Methods and Materials

Briefly, 0.7% of purified type I collagen fibers in 0.07M lactic acid were swollen and homogenized. Aliquots of dispersion were adjusted to pH4.8 to reconstitute fibers. Fibers were oriented, molded, lyophilized, crosslinked, rinsed, and sterilized. High (HD) and low (LD) density scaffolds were produced.

Effects of human PRP (RegenLab) on hASCs (ATCC) proliferation and differentiation into chondrogenic cells were investigated. 2 × 106 hASCs were seeded onto scaffolds (n=5), i.e., LD, HD, LD+PRP and HD+PRP. 1% PRP was added to the media. Cell viability (Alamar Blue assay) was measured. Differentiation (primers: Collagen I and Aggrecan) was performed with quantitative real-time polymerase chain reaction (qRT-PCR). Histology was used to evaluate cell distribution and ECM synthesis.

Data were analyzed using Analysis of Variance (ANOVA). Statistical significance was set to value ≤ 0.05.

Results

Fig.1A shows that the cell growth kinetics were similar. Fig. 1B shows PRP and scaffold density had a positive effect on type I collagen gene expression, where the highest effect was observed at day 21. Fig. 1C shows the effect of PRP on gene expression of aggrecan. The amount of aggrecan expression was significantly elevated in the presence of PRP by day 21, a sign of chondrogenic differentiation of hASCs.

1.png

Fig. 2 shows a cellular migration within the interior of the scaffolds in all groups at day 21.

2.png

Conclusion

This study shows that scaffold properties and PRP can play an important role in directing hASC towards chondrogenic differentiation in vitro. The effect of biomechanical stress produced by dynamic loading on the chondrogenic differentiation of hADSC is currently being investigated.

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Poster Biomaterials and Scaffolds

P041 - 3D Bioprinted GelMA-Gelatin-Hydroxyapatite Osteoblast Composite Hydrogels for Bone Tissue Engineering

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of this study was to investigate the suitability of an extrusion-based 3D bioink composed of gelatin methacryloyl (GelMA), gelatin, hydroxyapatite (HA), and osteoblasts for bone tissue engineering.

Methods and Materials

A mouse calvarial osteoblast-laden GelMA-gelatin bioink consisting of various concentrations of HA was 3D-bioprinted into porous hydrogel constructs. The constructs were cross-linked via photopolymerization and cultured in osteogenic medium. After 1, 14, and 28 days, the constructs were analyzed. The water weight percent differences of the hydrogels were characterized. An ALP assay and histological analysis were performed. Cell survivability and proliferation in the composite hydrogels was determined. Real-time polymerase chain reaction was performed to measure expression levels of osteogenic genes, BMP-7, and osteocalcin relative to a housekeeping gene (GAPDH).

Results

The addition of 5, 10, and 20 mg/ml of HA reduced hydrogel swelling from baseline GelMA-Gelatin hydrogels (p ≤ 0.01). HA decreased hydrogel breakdown in a concentration dependent manner (p ≤ 0.001). Alamar Blue assay demonstrated significantly increased cell proliferation. There was no difference in metabolic activity among the groups (p ≤ 0.01). The addition of 5mg/ml and 20mg/ml of HA significantly increased ALP expression at 7 and 28 days (p ≤ 0.05). Live/dead staining showed the majority of osteoblasts survived in all groups at 1, 14, and 28 days. The addition of 20mg/ml of HA (GG20HA) demonstrated greater BMP7 and BGLAP gene expression at both 14 and 28 days over hydrogels without HA (p ≤ 0.05).

ha figures.png

Conclusion

The addition of HA to GelMA-gelatin hydrogels significantly decreased hydrogel swelling, improved the ability to resist enzymatic degradation, increased osteoblastic differentiation and mineralization, and increased osteogenic gene expression while maintaining equal cell viability and proliferation to non-HA hydrogels. These findings support a lower threshold of 20 mg/ml of HA as an optimal concentration to support gene expression associated with osteoblast cell differentiation and maturation.

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Poster Biomaterials and Scaffolds

P042 - Covalent Protein Immobilization on Melt Electrowritten Microfiber Scaffolds for Guided Cartilage Regeneration

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Current tissue engineering treatments for end-stage articular cartilage fail to produce long-term functional cartilage tissue. Here, melt electrowriting (MEW) is used to fabricate 3D scaffolds with micro-resolution to mimic the properties of the native cartilage extracellular matrix (Castilho et al., 2019). These scaffolds are activated using atmospheric-pressure plasma jet (APPJ), allowing for covalent immobilization of transforming growth factor β1 (TGF), an important cytokine for the production and maintenance of cartilage (Wang, Rigueur & Lyons, 2014), onto the scaffold’s microfibers. It is hypothesized these biofunctionalized scaffolds will support differentiation of mesenchymal stromal cells (MSCs) into the chondrogenic lineage and subsequent neo-cartilage formation.

Methods and Materials

Poly-e-caprolactone MEW scaffolds were fabricated using a 3DDiscovery printer (regenHU), then activated using a computer-controlled APPJ device (Alavi et al., 2020). TGF was subsequently immobilized onto the MEW scaffolds using solution submersion (1µg/mL). Characterization of protein immobilization was performed using enzyme-linked immunosorbent assay (ELISA) and immunofluorescence detection. In vitro experiments were performed by seeding equine MSCs into the scaffolds and were cultured for 28 days. Neo-cartilage formation was quantified with dimethyl methylene blue/picogreen assays for glycosaminoglycan (GAG) production and confirmed with histological analysis.

Results

ELISA results confirmed covalent TGF concentration on the biofunctionalized scaffolds while immunofluorescently-labelled TGF was detected visually in scaffolds. The APPJ treatment caused increased hydrophilicity of the scaffolds, resulting in efficient cellular infiltration. In vitro analysis demonstrated that GAG production was significantly enhanced in both the immobilized TGF (+APPJ+TGF) and TGF (-APPJ+TGF) in medium groups, compared to the control groups without TGF supplementation (-APPJ+/-TGF). This finding was further validated by the heightened production of GAGs and collagen type II, observed in histological sections.

figure 1.jpg

Conclusion

We have demonstrated that APPJ-facilitated covalent immobilization of TGF retains bioactivity and stimulates differentiation of MSCs into the chondrogenic lineage. Our results also demonstrate that the new constructs with immobilized TGF support neo-cartilage formation.

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Poster Biomaterials and Scaffolds

P043 - Cartilage-Penetrating Hydrogel Mitigates Tissue Degeneration and Chondrocyte Catabolism

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
J. Patel, NovoPedics Inc, Consultant J. Patel, Forsagen LLC, Co-Founder

Abstract

Purpose

Cartilage injuries often result in progressive tissue degeneration, characterized by mechanical and biochemical loss. The purpose of this study was to determine the protective effects of a tissue-reinforcing hydrogel in slowing this deteriorative process.

Methods and Materials

figure1.pngCartilage explants (bovine trochlea) were trimmed to remove the superficial and calcified zones to simulate defected tissue. Plugs were kept in basal (control) or degenerative media (10ng/mL IL-1β), with hydrogel application at 0 and 1 weeks (Fig 1A/B). Methacrylated hyaluronic acid (MeHA; 4% w/v) with LAP photo-initiator (0.05% w/v) was applied to the explant surface, allowed 5 minutes to diffuse, and photo-crosslinked for 3 minutes. Four conditions were tested: Control, IL-1, Reinforced (MeHA at t=1w) and Pre-Reinforced (MeHA at t=0w). At two weeks, a biphasic creep test was performed to obtain biphasic mechanical properties. Samples were then subject to s-GAG quantification (DMMB), staining for proteoglycan content (Safranin-O/Fast Green) and breakdown (NITEGE - aggrecan neoepitope), and measurement of catabolic gene expression (MMP-13).

Results

figure2.pngCartilage fortification provided a protection of macroscale tissue mechanics in a degenerative culture (Fig 1C). s-GAG content of entire cartilage plugs showed no significant differences (Fig 1D). However, histological staining highlighted localized s-GAG depletion at the explant surface in degenerative media, while MeHA application led to enhanced s-GAG retention (Fig 2A/B). NITEGE exhibited a greater presence in the IL-1 group and mitigation in the MeHA-treated explants (Fig 2A/C). MMP-13 expression of IL-1 treated explants exhibited a 20+ fold increase, whereas reinforcement reduced these increases by more than half (Fig 2D).

Conclusion

Our MeHA hydrogel system, in a degenerative environment, provides protection from mechanical loss, improves s-GAG retention, and reduces matrix breakdown. This strategy could provide a simple yet effective treatment to halt the cartilage degenerative process. Future studies will explore these changes at the cellular level and translate this approach to an animal model.

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Poster Biomaterials and Scaffolds

P044 - A Personalized, Regenerative Implant for Open-Wedge Osteotomy - From Scan to Surgery

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Unicompartmental osteoarthritis of the knee joint can be treated with open-wedge osteotomy. However, the procedure faces several challenges as postoperative pain and non-union. Here, we aimed to design personalized implants using an osteopromotive and degradable biomaterial, that closes the gap left after an open-wedge osteotomy.

Methods and Materials

An open-wedge osteotomy procedure was preplanned using computed tomography (CT) scans. Based on this, a porous wedge scaffold was designed and printed using a magnesium strontium phosphate-polycaprolactone (MgPSr-PCL) biomaterial ink. The wedges were mechanically characterized and in vitro osteopromotive properties of the material were assessed using expanded human bone marrow-derived mesenchymal stromal cells (MSCs) and bone marrow concentrate (BMC). Next, personalized implants were fabricated for ex vivo implantation in three osteotomies with different heights (5 mm, 10 mm, 15 mm), and the wedges were implemented into the standard osteotomy surgical procedure in human cadaveric legs.

Results

Personalized wedge implants with inter-fibre spacing (IFS) of 0.7 mm, 1.0 mm, and 1.3 mm with closed outer edges were fabricated (Figure 1). Implants with IFS-1.0 resulted in scaffolds that maintained top and bottom porosity, while exhibiting significant mechanical stability. MSCs and BMC cells attached to the MgPSr-PCL material and proliferated over 21 days in culture. Alkaline phosphatase activity, calcium, and osteocalcin production were promoted in all culture conditions, independent of osteogenic induction medium. Finally, three “personalized” wedges were implanted ex vivo during a high tibial open-wedge osteotomy procedure. A small fraction of one side of the wedges were trimmed off to assure fit into the biplanar osteotomy gap. Pre-planned wedge heights were maintained after implantation as measured by micro-CT.

figure 1.png

Conclusion

To conclude, we have designed and manufactured personalized implants to fill the gap in open-wedge osteotomies. The implants supported osteogenesis of MSCs and BMC in vitro and were successfully implemented into the surgical procedure, without compromising pre-planned wedge height.

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Poster Biomaterials and Scaffolds

P045 - Elaboration of a Collagen-Enriched Bio-Ink for the Production of Zonal Specific Cartilage Substitutes

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
This work was supported by the “Fondation pour la Recherche Médicale”, grant number ECO201906008942 to Oceane MESSAOUDI.

Abstract

Purpose

In cartilage tissue engineering, 3D printing is thriving. The use of mesenchymal stem cells (MSCs), showing good proliferation and differentiation properties, enables the functionalization of printed constructs. The aim of our study was to assess the effect of different type I collagen quantity added in the bio-ink on the chondrogenic properties of MSCs to recreate the various layers of articular cartilage.

Methods and Materials

Bone marrow-MSCs were harvested from patients with osteoarthritis. After monolayer expansion, MSCs were suspended in an alginate-based bio-ink containing different quantity of soluble type I collagen: 0, 0.5, 1 and 5 mg/8mL of bio-ink. The constructs were bioextruded and polymerized. After 28 and 56 days of in vitro maturation, in a control media (ITS) or under a chondrogenic condition (ITS+TFG-β1), the cells viability, gene expressions (RT-qPCR) and matrix synthesis (histology and immunohistochemistry) were assessed.

Results

There was no effect of the global process on cell’s viability. After 28 days, the gene expressions show a chondrogenic differentiation of MSCs with TFG-β1. The quantity of 0.5mg enhanced the expression of chondrogenic genes, while 5mg induced a more osteogenic profile. At day 56, the matrix analyses highlight the positive effect of TFG-β1 on proteoglycan synthesis. An increase of type II collagen was observed with the lowest amount tested (0.5mg) whereas for the 5mg quantity was induced calcifications in the substitutes.

Conclusion

The use of an alginate-based bioink functionalized with MSCs, enables the production of cartilaginous substitutes with a chondrogenic gene expression profile and a proteoglycan rich matrix. The lowest quantity of collagen induces a more hyaline like matrix synthesis, suitable to recreate the more superficial cartilaginous layers. Furthermore, the quantity of 5mg causes the production of a calcified matrix more suitable for the calcified cartilage layer.

This work was supported by the “Fondation pour la Recherche Médicale”, grant number ECO201906008942 to Oceane MESSAOUDI.

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Poster Biomaterials and Scaffolds

P046 - Implantation of Genetically Modified Human Bone Marrow Aspirates by rAAV Vector via pNaSS-grafted PCL Film in Human Osteochondral Model

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Gene transfer using recombinant adeno-associated viral (rAAV) vectors is a powerful tool to enhance cartilage repair. Here, we tested the delivering therapeutic (chondrogenic sox9 and TGF-β) rAAV vectors in reparative human bone marrow aspirates by using poly (sodium styrene sulfonate) (pNaSS)-grafted poly(ε-caprolactone) (PCL) films for implantation in a human osteochondral defect model as a potential scaffold-guided gene therapy option.

Methods and Materials

The PCL films were tested in the following conditions: absence of pNaSS grafting (PCL conditions) versus pNaSS grafting (1.3 x 10-5 mol/g pNaSS; pNaSS-PCL conditions). rAAV-lacZ carries the E. coli β-galactosidase (lacZ) reporter gene, rAAV-FLAG-hsox9 a human sox9 sequence, and rAAV-hTGF-β a human transforming growth factor beta 1 sequence, all controlled by the CMV-IE promoter/enhancer. Immobilization of rAAV on the films was performed by adding the vectors (40 µl) with 0.002% poly-L-lysine. 150 µl of human bone marrow aspirates (hBMAs) were placed on the films with fibrinogen/thrombin and implanted in 4-mm diameter of human osteochondral defects (hOCDs) and kept in chondrogenic medium for 21 days. The biochemical assays and real-time RT-PCR analysis were assessed after 21 days. T-test was employed with P ≤ 0.05 considered statistically significant.

Results

Treatment with rAAV sox9 and TGF-β enhanced type-II collagen deposition in hBMAs via PCL film-guided gene transfer by implantation in hOCDs (Fig. 1 and Tables 1 and 2). Similar results were noted when measuring the normalized type-II collagen contents and increased the normalized proteoglycan contents but only with pNaSS-grafted films ((Tables 1 and 2). These results were corroborated by real-time RT-PCR of the profiles for COL2A1 and ACAN expression (Fig. 2) and reduced premature expression of COL1A1 and COL10A1 (Fig. 2).

fig.1 icrs 2022.jpgfig.2 . icrs 2022.jpg

Conclusion

These results show the potential of pNaSS-grafted PCL film-guided therapeutic rAAV gene transfer in hBMAs as a novel healing platform for implantation in articular cartilage defects.

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Poster Biomaterials and Scaffolds

P047 - Evaluation of Mechanical and Biomechanical Properties of Novel Meniscal Scaffold Using Bioabsorbable Materials

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

We have been developing a novel meniscal scaffold (PGA scaffold), which is consist of polyglycolic acid (PGA) covered with L-lactide-ε-caprolactone copolymer (P(LA/CL)). Meniscus acts as load distribution in the knee and the biomechanical properties are essential for the development of PGA scaffold. The purpose of this study was to evaluate the mechanical evaluation of the PGA scaffold and the biomechanical properties after PGA scaffold implantation using porcine knees.

Methods and Materials

Mechanical properties of PGA scaffolds were tested in a cyclic relaxation test from 0 to 7 N and were evaluated the stiffness of at time 0, 2 and 4 weeks of hydrolysis. The pressure sensor was used a pressure-sensitive conductive rubber sensor that is easy to mold, flexible, and resistant to shearing force. Contact pressure of meniscus was obtained from the pressure sensor using the medial meniscus and femur of the porcine knee. Three conditions of intact, meniscectomy, and scaffold implantation were prepared, and 100 N of compressive load was applied and contact pressure and area were calculated on lubber sensor, respectively.

Results

PGA scaffolds had the same strength as the initial stage up to 2 weeks of hydrolysis, and the strength of 4 weeks of hydrolysis was 72.3% of the initial strength (Fig. 1). The contact pressure was significantly higher, whereas the contact area was significantly smaller in the meniscectomy than in the intact (P < 0.05), however, the scaffold implantation recovered to the same contact pressure and contact area as well as the intact menisci (Fig. 2).

figure 1.png

figure 2.png

Conclusion

PGA scaffolds had an initial strength of 70% or more up to 4 weeks after surgery and indicating that the PGA scaffolds had been potential as the option of meniscus treatment in terms of improving mechanical properties after injury.

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Poster Biomaterials and Scaffolds

P050 - Generating Cartilage- and Meniscus-like Anisotropy in Poly(vinyl alcohol) Hydrogels

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
S. Bansal, AGelity Biomechanics S. Maher, AGelity Biomechanics, Grant Support T. Chen, AGelity Biomechanics, Grant Support

Abstract

Purpose

The objective of this study was to generate PVA hydrogels that mimic cartilage and meniscus anisotropy. We hypothesize that bending and circumferential forces will induce cartilage- and meniscus-like anisotropy, respectively, through a combination of tensile and compressive loads.

Methods and Materials

PVA solutions (20% w/v) were created as previously described in [1]. PVA was cast into custom-built 3D-printed molds; dogbones (25x5x5 mm) were cast for bending and “wedge shapes” (43x5x9 mm) were cast for circumferential loads. Cast PVA was partially crosslinked through three freeze/thaw cycles [1] and then samples were loaded. Bending was achieved through custom clamps built to fix samples in a U-Shape (Figure 1A) while circumferential loads were achieved by stretching wedges (250%) around a post (Figure 1B). All samples underwent an additional three freeze-thaw cycles while in the loaded configuration before characterization in which samples were visualized under a circular polarizer to determine zonal organization.

f1.png

Results

Samples undergoing bending exhibited a “neutral axis” along the mid-line of the sample with differing alignment above and below the axis (Mean difference: 29.43° ± 11.37°, Figure 2A). Circumferentially-loaded samples exhibited a less obvious neutral axis and instead a primarily tension-like phenotype oriented along a curve (Average range: -19.16° to 17.01°, average center ROI: 0.86°, Figure 2B).

f2.png

Conclusion

In this study, we were able to generate hydrogels with alignment that looks like cartilage and meniscus through the application of bending and circumferential loads. Previously studies have generated uniaxially aligned structures that mimic muscle and tendon [2,3], this work extends this concept to generate multidirectional anisotropy. The ability to generate biomimetic tissue replacements from a single material provides improved fracture toughness and longevity of the structures under cyclic fatigue loads [3]. Current work is underway to more completely characterize PVA hydrogel structures obtained through bending and circumferential loads.

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Poster Biomaterials and Scaffolds

P051 - Human articular chondrocyte re-differentiation in 3D-printed Platelet Rich Plasma (PRP)-alginate-based bioink

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Tissue engineering strategies for the clinical treatment of cartilage defects are mainly based on the transplantation of expanded autologous chondrocytes in vitro into the patient's damaged tissue. However, the differentiation of chondrocytes during in vitro expansion often leads to suboptimal results in the therapeutic intervention. Three-dimensional (3D) culture systems can restore this de-differentiated state and re-establish the chondrogenic phenotype. In this scenario, 3D bioprinting is a suitable technology for creating patient-shaped grafts from cell-laden bio-ink by layer-by-layer fabrication. This allows for a more physiological environment for transplanted cells, promoting tissue regeneration and repair.

Methods and Materials

Human joint chondrocytes (hACs) were isolated from patient tissue biopsies and expanded in vitro in a monolayer (2D culture). 3D bioprinting was performed by incorporating expanded hACs in mixed bioinks of platelet-rich plasma (PRP) alginate or alginate. Cell morphology, viability, growth, and chondrogenic differentiation were studied in vitro in both types of printed constructs.

Results

3D culture in both inks significantly increased the expression of chondrogenic markers compared to the 2D condition. Furthermore, the addition of PRP to the alginate upregulated the expression of these markers. Functionalization of PRP ink also increased the vitality, growth, and metabolic activity of hACs compared to alginate alone.

Conclusion

3D bioprinting of hAC allowed them to preserve the chondrogenic phenotype, furthermore, the use of bioink integrated with PRP supported the maintenance of metabolically active articular cartilage collagen type II positive. In view of future clinical translation, the choice of cell source for the 3D bioprinting of patient-specific grafts will have to be oriented towards cell types with a higher potential, such as chondro-progenitors, than mature hACs in order to ensure a more efficient regeneration and repair of cartilage.

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Poster Biomaterials and Scaffolds

P052 - Acceleration of Osteochondral Repair with a Growth Factor Loaded Collagen/Magnesium-hydroxyapatite Scaffold

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

A scaffold with a top layer of collagen layer and a bottom layer of collagen/Magnesium-hydroxyapatite (Mg-HA) layer has demonstrated good clinical results in osteochondral defects. Subchondral bone repair, however, remained suboptimal. In this study, we investigated the effect of the Mg-HA and addition of Bone Morphogenetic Protein 2 (BMP-2) or Platelet-Derived Growth Factor-BB (PDGF-BB) on the capacity of the scaffold to repair bone in an osteochondral defect.

Methods and Materials

Osteochondral defects were created in bovine osteochondral biopsies and implanted subcutaneously in athymic mice. To investigate the effect of the Mg-HA, osteochondral defects were filled with scaffolds consisting either of collagen-only or collagen/Mg-HA. To investigate the effect of growth factors 4μg BMP-2 or 100ng or 2μg PDGF-BB was loaded into the layered scaffold. The percentage of the defect filled with repair tissue was quantified on histology. Immunohistochemistry was performed to investigate inflammation. In vitro release of growth factors from the separate layers was measured with ELISA.

Results

Slightly more repair tissue, neutrophils and macrophages were observed after 4 weeks in defects filled with collagen/Mg-HA compared to collagen-only (Fig.1), indicating a positive effect of Mg-HA on tissue repair. The majority of PDGF-BB was burst released from both scaffold layers, whereas BMP-2 was bound and largely retained for 2 weeks in-vitro (Fig.2A,B). Moreover, the collagen-only layer released more BMP-2 than the layer with Mg-HA. In-vivo both growth factors might increase tissue repair after 4 weeks (Fig.2C,D), albeit statistical significance was not reached and after 8 weeks, bone was completely healed in this model, with and without growth factors.figure 1.pngfigure 2.png

Conclusion

Inclusion of Mg-HA in the collagen scaffold might accelerate tissue repair by a stronger initial inflammatory response. Loading BMP-2 or PDGF-BB into the scaffold might be promising to further accelerate bone repair and is further investigated in a goat model.

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Poster Biomaterials and Scaffolds

P053 - Differentiation Capacity of Rabbit Derived Chondrocytes Using Different FBS Concentration and Biophysical Stimulation

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

A widely used technique for the treatment of cartilage lesions is matrix-induced autologous chondrocyte implantation. However, in some cases the defect area is not sufficiently filled with hyaline cartilage matrix, so strategies need to be improved by tissue engineering approaches. One possibility represents the additional biophysical stimulation during pre-cultivation to promote differentiation of the cartilaginous cells. In order to investigate such an approach in an animal study, a prior analysis and parameter verification with suitable animal cells is necessary.

Methods and Materials

Chondrocytes derived from articular cartilage of New Zealand White rabbits were isolated and the optimal FBS concentration was verified for further biophysical stimulation experiments. Therefore, cells were cultivated with 1 %, 5 % or 10 % FBS in monolayers or on a collagenous scaffold over five days at 37 °C and 5% CO2. The most promising FBS concentration was used for further electrostimulation experiments. For this purpose, cells were seeded on collagenous scaffolds and exposed to alternating electrical fields ranging from 0.01 to 0.6 V/m for seven days according to Krueger et al. (2021). Afterwards, metabolic activity and gene expression levels of chondrogenic markers were analysed.

Results

While the metabolic activity of cells increased with higher FBS concentration, a simultaneous reduction in differentiation capacity (Col2: p=0.0024 1% vs. 10% FBS; p=0.0004 1% vs. 20% FBS) in 2D and 3D culture was visible. Electrical stimulation with very low levels of alternating electric fields (0.01 V/m) maintained chondrogenic differentiation capacity, with no significant changes compared to the control.

Conclusion

The results indicate that the FBS concentration directly affects cartilaginous cell metabolism and differentiation whereby 1% FBS showed the most promising results. Cell experiments with application of alternating electrical fields revealed less influence, however further experiments with a longer stimulation period as well as combination with mechanical stimuli are planned to increase chondrogenic differentiation.

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Poster Biomaterials and Scaffolds

P054 - Cartilage Oligomeric Matrix Protein C-terminus Peptides Bind TGFb-superfamily Growth Factors

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
D.R. Haudenschild and J.H.N. Yik are co-inventors on a patent related to cartilage oligomeric matrix protein (COMP).

Abstract

Purpose

BMP-2 and TGF-β1 belong to the TGFβ-superfamily of growth factors and are important for bone and cartilage development, respectively. Both growth factors are not freely diffusive, but bound to extracellular matrix (ECM) components that present these growth factor to cell surface receptors. Cartilage oligomeric matrix protein (COMP) is a major non-collagenous ECM protein found in bone and cartilage. We previously reported that COMP directly binds BMP-2 and TGF-β1 and enhanced their activity in osteogenesis and chondrogenesis, respectively. Here, we identified critical amino acid residues, residing in two separate regions within the C-terminus of COMP that are important for BMP-2 and TGF-β1 interactions.

Methods and Materials

28 nested peptides (15 aa in length) within the C-terminal domain of COMP were synthesized and tested for their abilities to interfere with the binding of full-length COMP to immobilized BMP-2 or TGF-β1 in a competitive ELISA assay. We identified two peptides, representing sequences YAGFIFGYQDSSSFY (aa 596-611), and CFSQENIIWANLRYR (aa 726-741) that interfere with COMP binding to BMP-2 and TGF-β1 (Fig 1A). Adjacent overlapping peptides did not interfere, which narrowed critical residues to the inner five of each peptide.

Results

icrs-figure_final.jpgicrs-figure_final.jpgThese two interfering peptides mapped to two distinct sites within the COMP C-terminal domain (Fig. 1B). Next, we tested different alanine scanning point mutants of each peptide in a competitive ELISA to identify individual residue(s) involved in BMP-2/TGF-b1 binding. Results showed that three residues (aa FGQ, FGQ, and GQD) within the first peptide were indispensable for BMP-2 binding, while four residues within the second peptide are partially responsible for binding interference (Fig 1C, D).

Conclusion

Further testing is required to confirm direct binding of these two interfering peptides to BMP-2/TGF-β1, and their effects on osteogenic and chondrogenic activities. These two interfering peptides have the potential to be developed as hybrid molecular carriers for BMP-2 and TGF-β1 in tissue engineering.

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Poster Biomaterials and Scaffolds

P055 - 3D Bioprinted GelMA-Gelatin-Hydroxyapatite-Demineralized Bone Matrix Osteoblast Composite Hydrogels for Bone Tissue Engineering

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Tissue engineering via 3D bioprinting offers a novel solution to treating large bone voids. The optimum bioink for bone tissue engineering is unclear. The purpose of this study was to investigate the suitability of an extrusion-based 3D bioink composed of gelatin methacryloyl (GelMA), gelatin, hydroxyapatite (HA), demineralized bone matrix (DBM) and osteoblasts for bone tissue engineering.

Methods and Materials

A mouse calvarial osteoblast-laden GelMA-gelatin-HA bioink consisting of various concentrations of DBM was 3D-bioprinted into porous hydrogel constructs. The 3D-fabricated constructs were cross-linked via photopolymerization and cultured in osteogenic medium. After 1, 14, and 28 days, a cohort of constructs were analyzed. The water weight percent differences of the hydrogels were characterized following fabrication along with the degradation behavior in standard culture medium for 28 days. Cell survivability and proliferation was determined.

Results

The addition of DBM to the bioink significantly decreased water content (%) from baseline GelMA-Gelatin-HA hydrogels with a significant trend of decreased swelling with increasing DBM content. The addition of 40, 80, and 120 mg/ml of DBM significantly reduced hydrogel swelling ratios (p ≤ 0.0001). DBM decreased hydrogel breakdown in a concentration dependent manner. Alamar Blue assay demonstrated significantly increased cell proliferation across groups. There was a slight trend of increasing metabolic activity with increasing DBM content. Live/dead staining at 1, 14, and 28 days after printing showed the majority of the osteoblasts were alive at each time-point.

screen shot 2021-10-11 at 10.54.57 am.png

Conclusion

Addition of DBM significantly decreased hydrogel swelling and suggests DBM to be essential in construct stability. DBM may also be altered to modulate the rate of degradation in vitro. Additionally, Alamar Blue results indicate that DBM addition to GelMA-Gelatin-HA bioink did not adversely affect cell viability and cells were able to survive the bioprinting process. These findings support GelMA-gelatin-HA-DBM as a viable bioink for bone tissue engineering.

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Poster Biomaterials and Scaffolds

P056 - Design of Non-viral Gene Activated Cryogels for Improving the Transfection of Human Mesenchymal Stem Cells.

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Gene-activated matrixes (GAMs) are promising tools for cartilage tissue repair due to their capacity to host selected cell populations, allowing for their transfection within the macroporous structure. In this study, we evaluated the potential of hyaluronic acid (HA)-based cryogels to host human mesenchymal stem cells (hMSCs) enabling their genetic modification by means a new niosomes-based formulation containing a reporter GFP plasmid (pGFP), while maintaining their viability.

Methods and Materials

Hyaluronic acid-based cryogels were synthetized by redox induced free-radical polymerization of MetHA in presence of ammonium persulfate (APS) and N,N,N′,N′-Tetramethylethylenediamine (TEMED). The resulting scaffolds (1 x 6 mm pieces) were characterized in terms of porosity, biodegradation, and shape memory ability. Cytotoxicity of resulting cryogels after the encapsulation of a hMSCs population, was evaluated using a calcein/propidium iodide staining and quantifying the amount of DNA in each sample at 7, 14 and 21 days. Finally, a new niosomes-based formulation complexing pGFP (P80PX nioplexes) was produced and its transfection efficiency of MSCs investigated, before and after being incorporated into the cryogels.

Results

Cryogels showed a macroporous structure (porosity percentage up to 90%) with biodegradation rate of ~50% after 21 days, and shape memory capacity over 99%. The results of the Live/Dead staining assay showed cytotoxicity profiles under 25% in all cases (Fig.1A) with increasing amounts of DNA after 21 days (Fig.1B). Of note, transfection efficiency of hMSCs with P80PX nioplexes was similar to that achieved with the commercial reagent Lipofectamine (Fig.2A) and showed a significantly lower cytotoxicity than this last one, in both monolayer cultures and when encapsulated into the matrixes (Fig.2B).

figure 1.jpgfigure 2.jpg

Conclusion

The developed systems were able to preserve the viability of hMSCs allowing for their proliferation and transfection in a 3D environment. Further studies including therapeutic genes to promote hMSCs chondrogenic differentiation will determine the potential of these matrixes as effective tools for cartilage repair.

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Poster Biomaterials and Scaffolds

P057 - Laser-Engraving Auricular Cartilage Scaffolds to Improve Scaffold Recellularization

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Recellularization still remains one of the main challenges to the use of decellularized cartilage materials for articular cartilage regeneration. With this objective, our group has previously developed two different strategies: i) laser-engraving of articular cartilage scaffolds, and ii) enzymatically treating auricular cartilage scaffolds. The current study aimed to combine the strength of both approaches by laser engraving auricular cartilage to 1) assess cellular infiltration and 2) determine the chondrogenic potential of those scaffolds for focal defect regeneration.

Methods and Materials

Auricular cartilage scaffolds were produced from 8mm biopsies of bovine ears as described previously [1]. In addition, they were laser-engraved with either a femtosecond (fs) or a CO2 laser. Distinct parameters were tested to achieve mechanically stable scaffolds. Furthermore, human articular chondrocytes (hACs) were used to evaluate cell migration into the scaffolds under dynamic culture conditions. To mimic a cartilage regeneration environment, scaffolds were cultivated in osteochondral cylinders with focal chondral defects.

[1] S. Nürnberger et al., ‘Repopulation of an auricular cartilage scaffold, AuriScaff, perforated with an enzyme combination’, Acta Biomater., vol. 86, pp. 207–222, 2019.

Results

The scaffolds laser-engraved with the fs-laser were mechanically more stable than those with the CO2 laser. However, fs lasered scaffolds were mainly repopulated on the surface. Cells were spanning over the narrow incisions, and only a few cells were found inside them. In CO2 lasered scaffolds, the incisions could be successfully reseeded with hACs, which were regularly distributed down to the tip and even spanning the interspace. Besides, some cells invaded the empty channels from the removed elastic fibres, either from the surface or the incision edge.

Conclusion

Laser-engraving is a potential tool to increase cell infiltration in decellularized auricular cartilage scaffolds. Further studies will be performed to evaluate the relevance for tissue formation and transplant integration into cartilage defects.

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Poster Biomaterials and Scaffolds

P058 - Autologous Matrix-induced Chondrogenesis (AMIC) in the Treatment of Grade IV Chondral Injuries of the Knee

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To evaluate the clinical outcomes of patients treated using AMIC with a hyaluronic acid scaffold in grade IV osteochondral lesions in the knee

Methods and Materials

Retrospective and multicenter study. To determine the clinical outcome of the patients the follow-up was done with the subjective International Knee Documentation Committee (IKDC) score, before the procedure, and with two subsequent evaluations. The present study was approved by the ethics committee of the participating health institutions and was conducted according to the principles expressed in the Declaration of Helsinki. For data analysis, GraphPad Prism V.7.0 software was used.

Results

Were followed 60 patients, for an average time of 24 months and with a mean age of 45 ± 12 years. Most patients were women. The mean size of the lesion was 3 cm2 and the injuries located in the patella and trochlear groove were the most frequent. The patients younger than 45 years presented better clinical outcomes than older ones. Similarly men presented better clinical outcomes than women and a negative correlation was found between the IKDC score and the age. There was a statistically significant improvement in all categories of the IKDC (symptoms, sports activities, function, and activity of daily living) compared between pre-surgery and last results. Besides, satisfactory results were achieved in patients with different clinical characteristics, such as the size of the lesion and its location, presence of injuries in multiple compartments of the knee, and even when the procedure was performed at the same time as the treatment of associated conditions. Likewise, all patients presented a high level of satisfaction with the procedure. Finally, no patient required additional surgeries, and no complications were reported during the follow-up period.

Conclusion

The repair of full-thickness chondral lesions of the knee using AMIC with hyaluronic acid scaffold provides satisfactory clinical results in the short- and medium-term follow-up.

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Poster Biomaterials and Scaffolds

P059 - Treatment of Patellar Cartilage Lesion with a Chitosan-based Scaffold: Clinical and MRI Results at Minimum 2 years of Follow-up

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

New cartilage regeneration techniques based on scaffolds have been recently developed to improve the results of microfracture treatment, also in complex locations like the patello-femoral joint. The aim of this study was to analyze the clinical and MRI results obtained exclusively in patellar lesions treated with a bioscaffold, a solution composed by chitosan and glycerophosphate which forms a stable clot into the lesion.

Methods and Materials

In this study,15 patients with ICRS grade 3 and 4 cartilage lesions of the patellar surface were enrolled and treated with chitosan bioscaffold. The mean age of patients was 31.8 ± 11.9 and nine patients presented degenerative etiology, while four patients had previous trauma and one patient was affected by patellar osteochondritis dissecans. The mean area of patellar chondral lesion was 2.90 ± 0.97 cm2. Patients were clinically evaluated up to 24 months with IKDC, KOOS and Tegner scores and they underwent MRI evaluation at 24 months.

Results

A statistically significant improvement was reported for the clinical score analyzed. The IKDC subjective score improved from 46.2 ± 19.3 preoperatively to 69.5± 20.3 (p<0.05) and 74.1 ± 23.2 (p<0.05) at 12 and 24 months, respectively. A similar trend was found for KOOS Pain, KOOS Sport/Rec, KOOS QOL, showing a significant improvement from baseline to 12 months and to the final follow-up. Finally, the total MOCART 2.0 score at 24 months after surgery was 71.5 ± 13.6.

Conclusion

Chondral patellar lesions represent a complex pathology, with lower results compared to other sites, probably related to the biomechanical and biological complexity of the patellofemoral joint. The results of the present study showed that this scaffold represents a safe surgical treatment providing a significant clinical improvement in the treatment of patellar cartilage lesions at 24 months also confirmed by promising MRI results.

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Poster Biomaterials and Scaffolds

P060 - Fixation of Osteochondral Defects in Pediatric Knee Using Biodegradable Magnesium Screws and Pins.

Presentation Topic
Biomaterials and Scaffolds
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
This research was funded by the Ministry of Health of the Czech Republic, grant number NU20-08-00150.

Abstract

Purpose

Magnesium alloy based implants represent relatively new generation of bioabsorbable materials appearing to be a promising alternative to the currently most widely used polymers. The purpose of this study was to evaluate the short-term clinical and radiological outcomes of the fixation of unstable or displaced osteochondral fractures and osteochondritis dissecans lesions in the knee joint using MAGNEZIX® screws and pins in pediatric patients.

Methods and Materials

12 patients (5 girls, 7 boys) were included in the study. Inclusion criteria were 1 / age < 18 years; 2 / unstable or displaced osteochondral laesions caused by injury or due to osteochondritis dissecans, classified according to ICRS; 3 / fixation with MAGNEZIX implants; 4 / minimum FU 12 months. X-rays and clinical evaluation were performed 1 day, 6 weeks, 3, 6, and 12 months after the operation, MRI scans 12 months after the surgery.

Results

The mean age at surgery was 13.3 ± 1.6 years. A total of 25 screws were used in 11 patients, mean 2.4 ± 1 per patient, 4 pins were used in 1 patient. In 2 patients the fixation was combined with fibrin glue. The mean FU was 14.2 ± 3.3 months. No intraoperative complications occurred. VAS for pain demonstrated significant improvement (from 4.8 before surgery to 1.2 after surgery). All patients showed full recovery of function and showed no signs of pain 6 months after surgery. No adverse local reactions were observed during follow-up. Complete radiographic (x-ray and MRI) healing occurred in all cases. Mild radiolucent zones were observed around the implants in the range of 6 weeks - 3 months. Areas of hypodensity suggesting new bone deposition corresponding with the former implant sites were observed on MRI at 12 months.

Conclusion

Fixation of osteochondral fragments by MAGNEZIX screws and pins during short-term FU provides sufficient stability and leads to uncomplicated healing.

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Poster Cartilage /Cell Transplantation

P062 - Juvenile Chondrocytes: Novel Alternatives for Allogeneic Cell Therapy?

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Development of novel allogeneic chondrocyte therapies are needed to provide a more widespread, cost-effective cartilage treatment option. Here we investigate the potential of juvenile cartilage sources for allogeneic chondrocyte manufacture.

Methods and Materials

Juvenile polydactyly digit (PD; n=4; aged 1±1 years (med±IQR)) or iliac apophysis cartilage (IA; n=6; aged 1±0.5years (med±IQR)) was used to derive chondrocyte cultures. Juvenile chondrocyte growth was compared to adult chondrocytes used for Autologous Chondrocyte Implantation (n=11; aged 41±9 years (med±IQR)). Further, juvenile chondrocytes (PD, n=2; IA, n=3) were up-scale manufactured using the Quantum® hollow-fibre bioreactor and compared to traditional tissue culture plastic (TCP) methods. All data are mean±SD.

Results

Comparable chondrocyte yields were obtained from juvenile (IA: 4.3±3.8x103 cells/mg tissue; polydactyly: 4.2±4.2x103 cells/mg tissue) and adult (2.6±0.1x103 cells/mg tissue; p>0.05; One-Way Anova) sources. In contrast, doubling time (DT) (passage 1-3) for PD chondrocytes grown on TCP (2.66±1.57days) was significantly lower than IA (5.17±2.66 days) and adult chondrocytes (9.98±10.29 days) (Paired t-tests; p<0.05). Up-scale bioreactor expansion yielded 74.5±30 x106 PD and 76±14x106 IA chondrocytes in 11±1 days. DT was longer in the bioreactor cf. TCP (IA: bioreactor DT= 3.9±0.2 days, TCP DT= 2.0±0.3 days, t-test, p<0.05; PD: bioreactor DT=3.8±1.0 days, TCP DT=1.3±0.0 days). Juvenile chondrocytes were immunopositive (>95%) for CD90, CD73, CD44, CD166 and CD151 and immunonegative (<2%) for CD19, CD34, and CD45 and no difference in immunoprofile was observed cf. TCP expansion (One-Way ANOVA).

Conclusion

Juvenile chondrocytes represent attractive allogeneic cells sources, yielding large numbers of chondrocytes. However, our preliminary analyses indicate that their growth may be slowed upon hollow-fibre bioreactor expansion. Further analysis of key chondrogenic genes and in vitro cartilage forming capacity needs to be conducted in more donors to determine whether chondrogenic potential is influenced by up-scale manufacture.

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Poster Cartilage /Cell Transplantation

P063 - Where is my Implant? Tracking of Fluorescence-labelled Chondrocyte Implants in Biodistribution Studies

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
P. Giesemann, CO.DON AG, Employee R. Kinne, BMBF, Grant Research Support (FKZ: 035577D) T. Rüdiger, BMBF, Grant Research Support (FKZ: 035577D) A.-K. Schubert, CO.DON AG, Employee L. Vonk, CO.DON AG, Employee

Abstract

Purpose

As an advanced therapy medicinal product (ATMP), autologous chondrocyte implantation (ACI) is subject to strict regulation, for example concerning the fate and biodistribution of the implant in a possible case of delamination. The present study assessed the stability of fluorescence labelling of chondrocyte spheroids with PKH26 in matrix-associated ACI and its applicability to recover the spheroids after a simulated biodistribution in the ovine stifle joint.

Methods and Materials

Ovine chondrocytes were labelled with PKH26 dye (Sigma-Aldrich) and cultured for 6 weeks in 3D environment for spheroid formation and general evaluation. After one week, 6 labelled spheroids were injected into the intact stifle joint capsule of merino sheep (n=3). After 9 days, the capsule of euthanised animals was opened to trace the labelled spheroids using a CO2-laser pointer (YAG 532 nm) and a long pass filter (EM LP590) or laser protection glasses (KTP/YAG LGF 532 nm) for detection. Detected spheroids were dissected and formalin-fixed for histological verification by haematoxylin-eosin (HE) staining.

Results

Labelling was stable in vitro for 6 weeks (Figure 1) and showed no impact on the spheroids’ common characteristics. PKH26-labelled spheroids appeared pink in visible light and red or yellow in fluorescent light, depending on the detection system (Figure 2). In vivo, all injected spheroids were recovered from different locations close to the injection site in the stifle joint capsule. HE staining confirmed the spheroids´ localisation in the connective tissue.

biodistribution_figure1.jpg

biodistribution_figure2.jpg

Conclusion

Fluorescence labelling was successfully used for visualisation, detection, and recovery of ectopically located chondrocyte spheroids in the ovine stifle joint. This technique may thus be suitable to recover delaminated or delocalised cell transplants and, in addition, to track down labelled chondrocyte spheroids in biodistribution studies.

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Poster Cartilage /Cell Transplantation

P064 - Allogeneic Chondrocyte Transplantation with Demineralized Bone Matrix Scaffolds to Repair Cartilage Lesions: A Rabbit Study

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To regenerate hyaline cartilage like tissue using demineralized bone matrix scaffolds with allogenic chondrocytes in a rabbit model.

Methods and Materials

fig. 1 biosponge.jpg

fig. 2 biosponge.jpg

Allogenic chondrocytes were isolated and cultured from a donor rabbit. Chondrocytes were first mixed with chitosan (1: 1 proportion), this to promote cell adhesion when the chondrocytes were seeded in the DBM (5x5mm), at a density of 2x106 cells, the implants were kept in culture for two days to achieve cohesion. The cellular-scaffold was implanted in a grade-4 chondral lesion in the trochlear groove of the rabbit’s knee. At 12 weeks the rabbits were euthanized, by RT-PCR and immunofluorescence analysis looking for the expression of the SOX9, COL2A1 and aggrecan genes and histological stains. Subsequently, the samples were analyzed histologically with the modified O'Driscoll scale.

Results

Neocartilage was formed in both the cellular-scaffold and control empty group. However, the structural integrity, integration and bone regeneration in the repair tissue appeared to be much better in cell-scaffold group (Fig. 1) compared to the control group. Histologically, the formation of hyaline cartilage is carried out in the chondral lesions where the scaffold was implanted, which is confirmed by the O'Driscoll scale (Fig. 2). Similarly, positivity is produced by means of immunofluorescence for markers such as Collagen type 2, Agrecan and Sox-9, as well as the gene expression of SOX-9, COL2A1 and ACAN through PCR.

Conclusion

The DBM scaffold is a viable option, with sufficient chondrogenic potential for the formation of hyaline cartilage, which can make chondrocyte implantation a technique accessible to the population of developing countries.

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Poster Cartilage /Cell Transplantation

P065 - Biotribological Tests of Inflammatory Osteochondral Plugs After Treatment with Hyaluronic Acid (HA), Glucocorticoids (GC) and HA/GC

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
This research was funded by Anika Therapeutics Inc.

Abstract

Purpose

The current study aimed to investigate the effects of hyaluronic acid (HA), glucocorticoids and (GC) and a co-administration (HA/GC) on cytokine-treated bovine osteochondral plugs under biomechanical stress via biotribological testing.

Methods and Materials

Osteochondral plugs were harvested from three bovine knee joints. The plugs were treated with (positive control) or without (negative control) pro-inflammatory cytokines (IL-1β, TNF-α, IL-6) for 1 week to simulate an OA environment. After seven days, the inflammatory medium was replaced by therapeutic medium (GC, HA, or GC/HA) for additional seven days. On day 14, biotribological testing was performed using PBS as a test fluid. Testing was standardized accordingly: an initial load of 180N for 10 minutes is followed by a resting phase of 10 min. This is followed by 3 cycles of repetitive sliding tests (2 mm/s at 180 N) for 10 minutes with a resting phase of 10 minutes between each cycle. The coefficient of friction (COF) was measured constantly during testing. Gene expression analysis, metabolic activity and measurements of sGAGs were carried out.

Results

In cytokine-treated plugs, COF increased compared to the negative control. HA led to decreased COF compared to positive control. Co-administration of HA/GC maintained the decreased COF. In all inflammatory conditions anabolic genes (COL2A1 and ACAN) decreased and catabolic genes (MMP1 and MMP13) increased compared to the negative control. Metabolic activity was lower in all inflammatory conditions compared to the untested control group at day 0. sGAG were increased in the positive control group compared to the negative control. HA and HA/GC decreased sGAGs compared to the positive control group and only adding GC alone.

Conclusion

Treatment of osteochondral plugs with HA led to a reduced COF and a decreased sGAG amount. A co-administration of HA/GC does not impair this effect. Thus, combining HA/GC has positive biotribological effects on bovine osteochondral plugs cultivated under inflammatory conditions.

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Poster Cartilage /Cell Transplantation

P067 - Assessing Allogeneic Chondroprogenitor Manufacture in Xeno-free and Serum-free Media

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

*SB and CHH joint first authors

Autologous Chondrocyte Implantation (ACI) requires a cartilage harvest and a subsequent cell implantation. There is a need to move towards therapies which are less invasive for patients and more cost-effective for health service providers. Allogeneic cells are one potential solution, but in order to manufacture them, alternatives for the autologous serum currently used in ACI protocols must be sought. To future-proof this process, a move towards xeno-free and serum-free protocols is also needed.

Methods and Materials

Chondroprogenitors were isolated from full depth human knee cartilage using selective adhesion to fibronectin and cryopreserved at passage 2-3 prior to use in these experiments. One ‘healthy’ cadaveric donor (a 22yo with no history of osteoarthritis/injury) and n=3 arthroplasty donors (mean 72yo) were included. Two xeno-free and serum-free GMP compliant culture media were tested for chondroprogenitors expanded on vitronectin (StemMacs MSC Expansion (media A; Miltenyi Biotech) and StemPro MSC Expansion (media B; Gibco)) cf. standard culture in DMEM/F12 with foetal bovine serum (FBS). Growth kinetics, immunoprofiling, gene expression analysis (RT-PCR) (n=4 donors) and chondrogenic analyses (n=2 donors) were performed for chondroprogenitors grown over passages 3 and 4.

Results

Chondroprogenitor manufacture in xeno-free and serum-free media does not significantly impact on their growth kinetics (population doubling level), immunoprofile (CD90, 73, 105, 44, 49c, 151, 29, 19, 34, 45, 49b, 14, 49a, 39 and HLA-DR) and, crucially, chondrogenic potential (GAG/DNA content), compared to FBS supplemented cultures. When expressed relative to FBS cultures, SOX-9 was significantly higher in media A cf. media B at passage 3. No other differences were found between expression levels in media A cf. B for any of the other genes tested (COLII, ACAN, COLX and ALK-1).

Conclusion

Our preliminary data suggests that xeno-free and serum-free media can be used to manufacture allogeneic chondroprogenitors without negatively altering their growth or phenotype.

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Poster Cartilage /Cell Transplantation

P068 - It Sticks, but why? Role of Different Adhesion Molecules during Initial Adhesion of a Cartilage Cell Implant

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
P. Giesemann, CO.DON AG, Employee A.-K. Schubert, CO.DON AG, Employee L. Vonk, CO.DON AG, Employee

Abstract

Purpose

Spheroids of human autologous matrix-associated chondrocytes are clinically available for autologous chondrocyte implantation (ACI). The cartilage cell implant attaches to the defect within 20 minutes without any further fixation. However, the mode of action of this adhesion process has not been elucidated yet. The aim of this study was to identify specific adhesion molecules involved in spheroid adhesion to the subchondral cartilage defect.

Methods and Materials

Chondrocytes were isolated from 8 donors (m/f 1:1, 54-76 years). Then, spheroids were generated, cultured for 2 weeks and implanted in an ex vivo human subchondral cartilage defect model [1] (70 spheroids/cm²) for adhesion experiments. At different time points after implantation (0, 10 and 20 minutes, 1, 4 and 24 hours), samples were taken for gene expression analysis of adhesion molecules CD44, dermatopontin, desmocollin 2, fibulin 7, integrin alpha 1, 2, 10 and 11, integrin beta 3 and transmembrane protein 204 using quantitative RT-PCR. Protein expression of CD44, integrin alpha 2 and integrin beta 3 was analysed immunohistochemically.

[1] C Bartz, J Transl Med. 2016 Nov 15;14(1):317. doi: 10.1186/s12967-016-1065-8.

Results

Implanted spheroids adhered to the defect ground, defect borders and to each other within 10 minutes. Within 24 hours gene expression of all adhesion molecules was upregulated in implanted spheroids compared to non-implanted spheroids (Figure 1). On protein level, CD44 and integrin alpha 2, but no integrin beta 3 expression was detected in both non-implanted spheroids and after implantation (Figure 2). Adhesion sites showed no expression of integrin alpha 2 and integrin beta 3. CD44 was detected in cells involved at the different adhesion sites and between implanted spheroids.

adhesion_figure1.jpg

adhesion_figure2.jpg

Conclusion

The gene expression profile of different adhesion molecules in the cartilage cell implant was changed after implantation. CD44 played a major role during adhesion, whereas integrin alpha 2 and integrin beta 3 were not involved.

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Poster Cartilage /Cell Transplantation

P069 - Mechanical Stimulation of Human Chondrocytes by Means of Hydrodynamic Shear Stress Supports Chondrogenic Differentiation

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

For the therapy of cartilage lesions, cell-based approaches may be associated with the formation of fibrocartilage tissue, resulting in a lower resistance to mechanical loading. The aim of the present in vitro study was to characterize the influence of hydrodynamic shear stress on human chondrocytes with regard to chondrogenic differentiation.

Methods and Materials

A standard 6-well cell culture plate combined with a linear piezo positioning system (Ziebart et al. 2018) was used for the application of hydrodynamic shear stress on human chondrocytes. For the experiments, 50,000 cells were seeded on collagen type I based scaffolds (Ø 10 mm). The sinusoidal micro motion with amplitudes of 25 µm, 50 µm and 100 µm were applied six hours per day over a period of seven days. After mechanical stimulation, metabolic activity of cells was identified. Additionally, analyses of important differentiation marker on gene expression and protein levels were performed.

Results

Compared to non-stimulated cells, metabolic activity increased with increasing amplitude, statistically significant for 100 µm (p = 0.0083). Furthermore, stimulation with 100 µm amplitude led to increased release of glycosaminoglycans and ACAN gene expression (p = 0.0071). Also increased Sox9 mRNA (p = 0.0129; 25 µm vs. 100 µm) and collagen 2 protein levels were observed. In contrast, collagen 1 content decreased with increasing amplitude. In addition, the underlying pathway appears to be triggered by PIEZO1 (p = 0.0082 non-stimulated control vs. 100 µm) rather than PIEZO2.

Conclusion

Through the targeted use of mechanical stimulation, physiological signaling pathways can be triggered and used for the directed differentiation of de-differentiated human chondrocytes. The combination with other types of biophysical stimulation, such as electrical stimulation, could further enhance the chondrogenic effects. Nevertheless, further investigations are needed to elucidate in detail the signaling pathways and biological effects of mechanical stimulation of hyaline cartilage by hydrodynamic shear stress.

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Poster Cartilage /Cell Transplantation

P070 - Hyaluronic Acid Supports the Effects of Cortison and Avoids Cytotoxic Effects of Local Anesthetics in Human Articular Chondrocytes in Vitro

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
The research was funded by Anika Therapeutics Inc.

Abstract

Purpose

The current study aimed to investigate the chondrotoxicity of co-administrating local anesthetics (LA) with glucocorticoids (GC) and hyaluronic acid (HA) in vitro.

Methods and Materials

Human articular cartilage was obtained from five patients undergoing total knee arthroplasty. Chondrocytes were isolated, expanded and seeded in 24-well plates for experimental testing. Local anesthetics (Lidocaine 1%, Bupivacaine 0,5%, Ropivacaine 2%) were used separately and co-administered with each of the following substances: GC (Triamcinolone Hexacetonide (TH) 4,5mg/ml), GC plus HA (TH: 4,5mg/ml, HA: 22 mg/ml), HA (22mg/ml). Cells were incubated with the various conditions for one hour, before substances were discarded followed by two washing steps. Culture medium was added, and cells were incubated for 24 hours. After 24 hours microscopic images were taken, and metabolic activity was measured. Also, a viability assay using flow cytometry was performed.

Results

The addition of HA and GC/HA resulted in enhanced attachment and branched appearance of the chondrocytes compared to LA and LA/GC. Metabolic activity was better in all LA co-administered with HA and GC/HA than with GC and only LA (Figure 1). Flow cytometry revealed the lowest cell viability in lidocaine and the highest cell viability in ropivacaine (Figure 2). This finding was also confirmed by the live/dead assay.

figure_1.jpg

figure_2.jpg

Conclusion

In conclusion, HA supports the effect of GC and reduces chondrotoxic effects of LA in vitro. Thereby the co-administration of HA to LA and GC offers an alternative less chondrotoxic approach for treating patients with symptomatic osteoarthritis of the knee.

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Poster Cartilage /Cell Transplantation

P071 - Inhibition of Transcription Factor Twist1 Promotes Stromal Cell-Based Cartilage Repair

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Placenta-derived Mesenchymal stromal cells (PMSCs) have been widely explored for tissue engineering applications and demonstrated capacity for chondrogenic differentiation. However, rapid induction of PMSC chondrogenic differentiation during therapeutic transplantation remains extremely challenging. This study is to determine if Twist1 inhibition could be utilized to accelerate PMSC-mediated cartilage repair in a cartilage defect model.

Methods and Materials

PMSCs were isolated from human placenta delivered from normal term. Cell phenotype was evaluated by flow cytometry, in vitro osteogenic, chondrogenic and adipogenic differentiation assays. Lentivirus-mediated gene silence was used to inhibit Twist1 in PMSC pellet culture. A mouse knee joint cartilage defect model was used for in vivo study. Wild type and Twist1 deficient PMSC pellets were generated and inserted to fill the cartilage defects. After 4 weeks postoperatively, osteochondral units containing the defects were harvested for Alcian Blue/Orange G staining, Immunohistochemical staining (IHC) and RT-PCR analysis.

Results

The flow cytometry results indicated that human stromal cell markers CD29, CD73, CD90 and proliferation marker Ki-67 were highly expressed in PMSCs, and these cells could be induced into osteoblasts, adipocytes and chondrocytes in vitro. Particularly, silencing Twist1 significantly enhanced chondrogenesis in pellet culture by showing increased Alcian blue staining, enhanced type II collagen (Col-II) expression when compared to control PMSCs. Importantly, the in vivo transplantation of Twist1-deficient PMSCs into knee joint cartilage defects had a significantly enhanced cartilage formation when compared with wild type PMSCs at 4 weeks after operation. Finally, our PCR data showed an increased expression of chondrogenic markers Sox9, Col-II and aggrecan in knee joint tissue with transplantation of Twist1 deficient PMSCs.

Conclusion

These findings demonstrate that 1) PMSC is a favorable cell source for cartilage repair. 2) Silencing Twist1 could accelerate PMSC differentiation into chondrocyte in vivo. Our results strongly suggest that targeting Twist1 in stromal cells may be a promising strategy for cartilage regeneration.

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Poster Cartilage /Cell Transplantation

P072 - Propofol as Anaesthetic – Does it Impair Manufacturing of Autologous Chondrocyte Implantation Products?

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
A.Schubert, CO.DON AG, Employee, G.Roël, CO.DON AG, Employee, P Giesemann, CO.DON AG, Employee, C.Kaps, CO.DON AG, Employee, L.Vonk,, CO.DON AG, Employee, A.Hoburg, CO.DON AG, Consultancy

Abstract

Purpose

In clinical practice, human autologous chondrocytes are used for implantation to treat cartilage defects. For chondrocyte culture, autologous serum is often used as supplement in the culture medium. It is under discussion, whether drawing the blood during anaesthesia for the cartilage biopsy harvest impairs the manufacturing of the autologous cell implant. Since many clinicians use the anaesthetic propofol, we investigated a possible impact of propofol on cell’s performance during cell expansion and 3D culture.

Methods and Materials

Blood was obtained from 10 donors (male/female 4/6, 30-49 years) before and after propofol administration (1% in soy oil, 2,3-4,2 mg/kg/h, 4-21 minutes after administration) to generate serum without and with propofol. Human primary chondrocytes were isolated from 3 donors (male/female 2/1, 56-76 years). Cell expansion and 3D spheroid formation were performed using both normal serum and serum with propofol (n=10). Cell adhesion was evaluated 5 days after seeding and gene expression of cartilage-matrix proteoglycan aggrecan (ACAN) was measured in chondrocyte spheroids after two weeks of culture.

Results

Serum with propofol was cloudy in 8/10 batches. Chondrocytes were expandable and 3D spheroids were formed using both serum with and without propofol. However, the propofol group showed lower cell adhesion in 5/10 batches (Figure 1A) and 3 of these showed less population doublings in P0 (Figure 1B) and thus additional passaging was necessary to achieve similar cell yields. ACAN gene expression was decreased in 3 spheroid cultures in the propofol group (Figure 2).

propofol_figure1.jpgpropofol_figure2.jpg

Conclusion

In presence of propofol, chondrocytes could still grow in 2D culture and assembled as spheroids in 3D culture. However, serum enriched with propofol may affect initial cell adhesion, to extend cell culture time, or change cartilage-specific gene expression in some chondrocyte cultures. Therefore, it is not recommended to draw the blood for autologous serum applications from the patient under anaesthesia with propofol.

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Poster Cartilage /Cell Transplantation

P074 - Validation of Open and Arthroscopic Size Measurement of Osteochondral Lesions of the Ankle in Comparison with Arthrography Imaging

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
This study was funded by the Alwin Jäger Stiftung.

Abstract

Purpose

For the treatment of talar osteochondral lesions (OCLT) the defect size is highly relevant. In addition to intraoperative defect size measurement, preoperative planning by means of magnetic resonance imaging (MRI) or computed tomography (CT) is crucial.

Methods and Materials

Four defects each of different sizes and depth were created on the talus (anteromedial/-lateral, posteromedial/-lateral) in a total of 14 cadaver feet. All defects were evaluated by each of three foot and ankle surgeons arthroscopically and via a mini-arthrotomy. Arthro-MRI and high resolution flat panel CT arthro (FPCT-A) scans were acquired. Two radiologists independently performed size measurement of every OCLT on MRI and data. Length, width and depth were measured for every defect and the defect volume was calculated. To determine the exact defect size and volume, each talar defect was filled with plastic pellets. The defect impressions were scanned in an FPCT, in order to create a 3D multiplane reconstruction data set for measurement of the exact defect size and volume. Finally, the surgically measured values were compared with the radiological values and the exact defect size.

Results

Surgically measured values for defect length, width and depth underestimated the exact defect size, both arthroscopically and open (p<0.05). Arthroscopically determined defect length and width showed the largest deviation compared to the exact size (p<0.05). The measured CT values demonstrated higher correlation with the surgical measurements, both arthroscopically and open, compared to MRI measurements (p<0.05). The defect depth was determined most accurate with an FPCT scan compared to the exact defect size (p<0.05). The calculated surgically determined defect volume overestimated the exact defect volume (p<0.05).

Conclusion

The measured FPCT defect sizes displayed higher correlation with the surgically measured values compared to the MRI. However, the exact defect size is underestimated surgically. FPCT-A scan is best qualified to assess defect depth.

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Poster Cartilage /Cell Transplantation

P075 - Preclinical Studies Using Rapidly Isolated Human Nasal Chondrocytes for a Single-stage Arthroscopic Cartilage Regeneration Therapy

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Gyözö Lehoczky was partially supported by a research grant by the Department of Surgery of the University Hospital of Basel.

Abstract

Purpose

Nasal chondrocytes (NCs) have a higher and more reproducible chondrogenic capacity than articular chondrocytes and the engineered cartilage tissue they generate in vitro was demonstrated to be safe in clinical applications. Here we aimed at determining the feasibility for a single-stage application of NCs for cartilage regeneration under minimally invasive settings.

Methods and Materials

Fresh nasal septal cartilage grafts were digested according to a new, rapid protocol. Cell yield, viability, proliferative and chondrogenic capacity were assessed. The unexpanded (p0) NCs were delivered in a degradable polyethylene glycol (PEG) gel enriched with pooled human platelet lysate (hPL) extract, in low density (300.000 cells/mL gel), and cultured in vitro and in vivo. Histological, immunofluorescence and biochemical analyses were carried out at day 0, after 1 and 4 weeks. For in vivo tests, an ectopic human osteochondral model was used to create full thickness cartilage lesions of 4 mm diameter, filled with low-density, p0 NCs in hPL-PEG gel (without in vitro pre-culturing), and implanted subcutaneously in nude mice for 8 weeks.

Results

"Rapidly isolated" NCs show similar viability, chondrogenic and proliferative capacity compared to standard digestion; however, cell yield is even higher after the new protocol (mean 4.8x106 ± 3.5x106 vs. 3.3x106 ±2.7x106 cells/gram of tissue, p= 0.0135). NCs embedded in hPL-PEG gels efficiently proliferated (total of 6.33 ±0.51 population doublings in 4 weeks) and generated tissue rich in hyalin cartilage-specific glycosaminoglycans (GAG) and type II collagen, with GAG/DNA ratio of mean 12.3 (±7.9). NC-hPL-PEG gels developed into hyaline-like cartilage tissues upon ectopic in vivo implantation and morphologically integrated with surrounding native cartilage and bone tissues in situ.

Conclusion

Our findings collectively indicate that this could be a feasible strategy for cartilage repair and now requires further validation in orthotopic in vivo models.

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Poster Chondrocytes

P076 - Treatment of Bilateral Knee Chondral Defects with High-Density Autologous Chondrocyte Implantation (HD-ACI)

Presentation Topic
Chondrocytes
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Bilateral knee chondral defects are uncommon and they can be treated in one or two surgical acts, each of one having pros and cons. In this work we have studied the clinical outcome of patients with bilateral knee chondral defects treated with High-Density Autologous Chondrocyte Implantation (HD-ACI) during the same surgery

Methods and Materials

Eight patients (4 women and 4 men) with chondral defects in both knees treated with HD-ACI during the same surgical act were included. Patients were evaluated 2, 6, 12 and 24 months post-op for treatment safety and efficacy. Safety was tested with the visual analogic scale (VAS) for pain, International Knee Documentation Committee (IKDC) for subjective patient’s perception of both knees and EuroQol five-dimensional five-level questionnaire (EQ-5D-5L) for quality of life. Integrity of neo-formed tissue at 12- and 24-month follow-up was assessed by the magnetic resonance observation of cartilage repair tissue (MOCART) score

Results

VAS decreased from baseline to 24 months from a median of 8 (6 – 9) to a median of 0 (0 – 5) (p<0.001). IKDC increased from a median value of 39.0 (17.2 – 48.3) in the basal visit to a median of 83.7 (24.0 – 98.0) in the 24-month visit (p<0.001). EQ-5D-5L decreased at 2 months post-op and increased throughout the follow-up visits thereafter, needing 24 months after surgery to reach a value higher than the basal one. Median MOCART at 12 months was 80.3 (58.0 – 89.7) and 81.3 (54.0 – 89.9) at 24 months

Conclusion

Treatment of both knees with HD-ACI during the same surgical act in patients with bilateral chondral lesions is a safe procedure, providing good clinical results

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Poster Cartilage /Cell Transplantation

P077 - Cell number influences the clinical results of one-step bone marrow derived cell transplantation for OLT treatment

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Bone marrow aspirate concentrate (BMAC) seeded in situ onto a scaffold provided satisfactory results for the treatment of osteochondral lesions of the talus (OLT). However, no studies evaluated the relationship between the therapeutic effect of this arthroscopic technique and the number of mononuclear cells (MNCs) in BMAC. Aim of this study was to investigate the impact of the number of cells in BMAC on the clinical outcome of a bone marrow derived cell transplantation (BMDCT) technique in patients with OLTs.

Methods and Materials

A total of 143 consecutive patients with OLTs (area >1.5 cm2) were treated with a BMDCT technique: BMAC was harvested from the posterior iliac crest and seeded onto a hyaluronic acid membrane. Patients were evaluated with the AOFAS score before the treatment and up to 60 months of follow-up. For 100 of these patients, 2 ml of bone marrow aspirate (BMA) and 2 ml of BMAC was collected and used for MNCs count. A statistical analysis was performed to investigate the influence of the number of MNCs on clinical outcomes.

Results

Mean AOFAS score improved from 58.3 ± 13.4 preoperatively to 87.4 ± 15.9 at 60 months (p < 0.0005). BMA from the iliac crest contained a mean of 27.7 ± 8.9 x 103/μL MNCs and the BMAC contained 151.6 ± 56.4 x 103/μL MNCs. Higher number of MNCs in BMA positively correlated with AOFAS score at 36 months of follow-up (Rho = 0.275, p = 0.021). Higher number of MNCs in BMAC positively correlated with AOFAS score at 60 months of follow-up (Rho = 0.509, p = 0.007).

Conclusion

One-step BMDCT obtained positive results up to 60 months of follow-up in patients with OLTs. The number of MNCs in BMAC seems to positively influence the clinical outcome obtained with this arthroscopic procedure.

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Poster Cartilage /Cell Transplantation

P079 - MCID and PASS in Patients With Knee Osteoarthritis Treated With PRP Injection

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
S.Z. has received institutional support from Fidia Farmaceutici, Cartiheal, IGEA Clinical Biophysics, Biomet, and Kensey Nash; grant support from I+; and royalties from Springer. AOSSM checks author disclosures against the Open Payments Database (OPD). AO

Abstract

Purpose

To establish the Minimal Clinically Important Difference (MCID) and the Patient Acceptable Symptom State (PASS) for the International Knee Documentation Committee (IKDC) Subjective score and the Knee injury and Osteoarthritis Outcome Score (KOOS) in patients treated with platelet-rich plasma (PRP) injections for knee osteoarthritis (OA).

Methods and Materials

This study included 215 patients with knee OA (68% men, 32% women; age, 53.2 ± 11.3 years) who underwent PRP injections. Patients were assessed through the IKDC Subjective score and KOOS subscales, and the MCID and the PASS for both measures were independently calculated at 6 and 12 months post-injection. The MCID was calculated using the value equal to half of the standard deviation of the overall cohort improvement. The PASS was assessed using a 2-point scale (satisfied or not satisfied), with threshold values being detected through a receiver operating characteristic curve analysis and the Youden index to maximize the sensitivity and the specificity of the threshold values.

Results

All scores improved significantly from baseline to 6 months and baseline to 12 months (P < .001 for all scores). All scores were stable from 6 to 12 months except for the KOOS Quality of Life subscale, which improved further (P = .033). For the IKDC, the MCID values were 8.6 and 8.5 points and the PASS scores were 59.7 and 62.1 at 6 and 12 months, respectively. The MCID and the PASS for all KOOS subscales remained constant at the 2 follow-up points. The percentage of patients who achieved the MCID and the PASS was higher than 85% at both 6 and 12 months post-injection.

Conclusion

This study provided the MCID and PASS thresholds for the IKDC and KOOS scores in patients with knee OA treated with PRP injections. These psychometric measures may allow a better interpretation of the clinical relevance of injection-based treatment outcomes for knee OA.

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Poster Cartilage /Cell Transplantation

P080 - Results of Meniscal Transplants Over a 13 Year Study Period

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To identify trends in results for patients who underwent a meniscal transplant performed by a single surgeon based off patient recorded outcomes at measured intervals of 6 weeks, 12 weeks, 6 months, and every year after surgery. In patients status-post meniscectomy, meniscal allografts transplantation (MAT) has been used to restore the normal biomechanics and anatomy of the knee. Numerous studies have shown that this is a viable option to restore this vital, missing tissue. MAT has been previously shown to yield favorable results and provide both improved function and pain in the short- and medium-term basis.

Methods and Materials

The aim of this study is to evaluate patient recorded outcomes in the short-, medium, and long-term basis in patients who underwent MAT performed by a single surgeon utilizing a bone-block technique. From November 2012 through January 2019, 16 isolated MATs were performed by the senior author in previously meniscectomized patients with corresponding compartmental knee pain. Summaries for pain frequency and severity were calculated at measured intervals. Variables were compared over time with a nonparametric repeated measures model.

Results

16 patients with minimum one-year post-operative follow up demonstrated statistically significant improvements in at all time points in seven of nine of standardized outcomes surveys with the exception of MSF-12 and PSF-12 (Fig 1). Median preoperative pain frequency and pain severity scores were 7 and 6.5 respectively, whereas these scores each decreased to 3.5 at one-year follow-up and to 1.5 at two-year follow-up.figure 1 mat icrs.jpg

Conclusion

Meniscus transplantation in isolation resulted in reliable improvements in knee pain and function at minimum 1-year follow-up, although overall, scores demonstrated best results at the 2-year follow up interval. Our findings agree with preceding studies demonstrating that when done in the correct patient population, MAT (specifically utilizing bone fixation), provides an excellent graft which provides long-term improvements (Fig 2).fig 2 mat icrs.png

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Poster Cartilage /Cell Transplantation

P081 - Long Term Functional and Clinical Outcomes After Patellar Osteochondral Autologous Transplantation: Minimum 5 Years Follow up

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The aim of the present study was to assess clinical and functional evaluation of patients submitted to osteochondral autologous transplantation of the patella in a long term follow up

Methods and Materials

In this prospective study, thirty-four patients with a symptomatic full-thickness patellar chondral injury surgically treated with osteochondral autologous transplantation were evaluated at 3 occasions: preoperatively, 2 years and minimum 5 years (maximum 11years) after surgical treatment. Lysholm, Kujala, and Fulkerson scores, Tegner Scale, the Short Form-36 health survey and overall treatment failure were assessed as outcomes.

Results

Thirty-four patients were assessed with an average follow-up of 90.88 months (138-60); 19 were female. On the Lysholm scale were obtained the following scores: 57,8; 79,9; 77,9, on the preoperative, at 2 years and at the final follow-up (p<0,001; p=0,085), respectively; for Fulkerson the scores were: 54,4; 81,3; 79,7 (p<0,001; p= 0,883), respectively; for Kujala the scores were 5,5; 79,5; 78,9(p<0,001), respectively; and for the Tegner scale, evaluated only on the preoperative and the final follow up: 6,59; 5,47 (p=0,007). The failure prevalence, defined as the need of another surgical procedure, was 17.64%.

Conclusion

Autologous osteochondral transplantation is an effective technique for the treatment of patellar osteochondral lesions and the outcomes assessed in the short term did not deteriorate over a follow up of 5 to 10 years.

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Poster Cartilage /Cell Transplantation

P083 - Cartilage Regeneration with an Umbilical Cord Blood-derived Mesenchymal Stem Cell Implantation on Knee OA Patients with HTO

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Among various restorative cell-based cartilage treatments, the use of umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation with concomitant HTO procedure is used to improve clinical and anatomic outcomes in patients with varus malalignment and medial compartment osteoarthritis.

Methods and Materials

We retrospectively evaluated a total of 146 patients who were performed open wedge HTO procedure and hUCB-MSC implantation from 2013 to 2021. We categorized those with HTO only as group A (23 patients) and those with HTO and hUCB-MSC implantation as group B (40 patients). At 12th month postoperatively, the cartilage regeneration was assessed macroscopically based on ICRS grading system and Oswestry Arthroscopy Score (OAS); in addition, the location, size, and histological assessment of cartilage lesions were further evaluated. International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcomes Scores (KOOS), and VAS scores were evaluated for secondary clinical outcome measures at preoperatively and last follow-up.

Results

At median follow-up periods of 2.3 years, clinical scores (IKDC, KOOS, and VAS scores), all improved from preoperative to the last follow-up in both groups with statistical significance. Both groups showed improved postoperative lower extremity alignment, indicating hip-knee-ankle angle from 7.19 to 2.1 in Group A and from 8.25 to 2.54 in Group B. However, Group B showed better macroscopic appearances and characteristics in chondral regeneration (26.3% of patients improved to ICRS Gr I, 53.1% to ICRS Gr II, 3.3% to ICRS Gr III) than Group A (12.6% of patients improved to ICRS Gr I, 27.5% to ICRS Gr II, 33% to ICRS Gr III). In addition, macroscopic evaluation of cartilage repair based on OAS scoring also indicated similar results (mean 7.52 points in group A and mean 3.56 points in Group B).

Conclusion

hUCB-MSC implantation with concomitant HTO procedure for medial compartment osteoarthritis was safe and indicated better signs of cartilage repair status compared to HTO alone.

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Poster Cartilage /Cell Transplantation

P084 - Long Term Outcomes And Survivorship Of Autologous Chondrocyte Implantation For Femoral Condyle Articular Cartilage Defects In The Knee

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The aim of this study is to report long-term outcomes of ACI for isolated femoral condyle articular cartilage defects. The relationship between cell numbers, cell growth kinetics and clinical outcome will be discussed.

Methods and Materials

Prospectively collected data of 41 patients with a single medial or lateral femoral condyle articular cartilage lesion treated with ACI were identified from an in-house cell therapy database and analysed. The mean patient age was 36.5 years (±9.0, range 18-52) with 29 males and 12 females. Thirty lesions were on the medial femoral condyle and eleven were on the lateral femoral condyle. The mean area of defect was 4.38cm2 ±3.11 with the largest defect area measuring 13.5cm2. The mean number of cells implanted was 3.01 x 106 ±6.24 x 106 cells/cm2. Clinical outcome was determined annually using the modified Lysholm score, which was analysed using multilevel modelling. Kaplan-Meier survival analysis was performed using total knee replacement as the endpoint.

Results

The mean follow-up time was 11 years (± 5.03) with a maximum follow-up of 20 years post-ACI. The mean pre-operative Lysholm score was 43 ±17.16. Improvement in clinical outcome scores were found to peak between years 7-9 with a mean score of 61.0 (95% CI [54.3, 67.7]). Mean Lysholm scores at 10 and 20 years post-ACI were 60.9 (± 3.46) and 57.1 (± 6.98) respectively. Eight patients were considered to have failed with a conversion to total knee arthroplasty at a mean time of 8.1 years following ACI. Survival at 20 years was 74.4% (95% CI [60.3, 91.8]) with maintenance of the native knee for which treatment was initially sought.

Conclusion

The results show that ACI provides good survival rates and improved clinical outcome scores with enduring long-term results. It is a viable and valuable option for the management of isolated chondral defects in the femoral condyle of the knee

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Poster Clinical Outcome

P085 - Non-Arthritic Hip Pathology Patterns According to Gender, Femoroacetabular Impingement Morphology and Generalized Ligamentous Laxity

Presentation Topic
Clinical Outcome
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Financial interests: Amplitude, Arthrex, ATI, Breg, DJO Global, Kauffman Foundation, MAKO Surgical, Medacta, Medwest, Orthomerica, Pacira Pharmaceuticals, Stryker Affiliations: American Hip Institute, Hinsdale Orthopaedics, North Shore Surgical Suites,

Abstract

Purpose

To identify hip pathology patterns according to gender, alpha angle deformity and generalized ligamentous laxity (GLL) in a non-arthritic patient population following primary hip arthroscopy for femoroacetabular impingement syndrome.

Methods and Materials

Patients who underwent primary hip arthroscopy between February 2008 and February 2017 were included and separated into males and females for initial analysis. The demographics, radiographic findings, intraoperative findings, and surgical procedures were then compared. A threshold of one standard deviation above the mean alpha angle in the male group was used to create two sub-groups. For females, GLL based on a Beighton’s score ≥4 was used to divide the group.

Results

A total of 2701 hips were included. Of those, 994 hips were in the male group and 1707 hips in the female group. Mean age was 36.6 years±13.8 and 37.1 years±15.0 for the male and female groups, respectively. The male group had a higher average alpha angle when compared to females [65.9°±11.9 vs 58.4°±10.8 (P<0.001)]. GLL was more common in females than males (P< 0.001). The male group had a higher proportion of acetabular Outerbridge grade 3 and 4 lesions compared to the female group (P<0.0001). Males in the alpha angle ≥78° sub-group reported higher rates of acetabular Outerbridge grade 4 damage than males in the <78° one (P<0.0001). Mean lateral center-edge angle was lower in the Beighton ≥4 female sub-group [23.7°±4.2 versus 31.3°±5.8 (P<0.0001)].

Conclusion

Two different patterns of hip pathologies were found to be related to gender. On average, male patients had higher alpha angles and increased acetabular chondral damage when compared to the females. A larger cam-type anatomy was associated with more severe acetabular chondral damage in males. In the female group, the incidence of features of hip instability such as GLL were significantly higher than in the male group.

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Poster Cartilage /Cell Transplantation

P086 - Costal Chondrocyte–Derived Pellet-Type Autologous Chondrocyte Implantation for Repair of Articular Cartilage Defects

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To study the efficacy and safety results at 5 years after treatment with costal chondrocyte-derived pellet-type autologous chondrocyte implantation for repair of articular cartilage defects of the knee.

Methods and Materials

This article describes the 5-year follow-up of the previous prospective clinical trial that compared the results of Costal chondrocyte-derived pellet-type autologous chondrocyte implantation versus microfracture at 2-year follow-up. Of the 20 patients from the Costal chondrocyte-derived pellet-type autologous chondrocyte implantation group that were described in the previous study, 12 were followed-up at 5 years. Clinical outcomes scores including IKDC, Lysholm, KOOS score, and 100 mm pain VAS score and MOCART score from magnetic resonance imaging was performed at 5-year follow-up.

Results

There were no treatment-related serious adverse events during the 5-year follow-up period. Significant improvements were seen in all clinical scores from the preoperative baseline to the 5-year follow-up (IKDC score, from 38.2 to 70.7, P < 0.0006; Lysholm score, from 47.5 to 81.7, P < 0.0003; and KOOS score, from 54.1 to 82.5, P < 0.0022; 100 mm pain VAS score, from 59.3 to 17.2, P < 0.0001). Significant improvement was seen in MOCART score from preoperative baseline to the 5-year follow-up (18.1 to 70.9, P < 0.0001).

Conclusion

The overall results of the 5-year follow-up of this clinical trial suggest that the efficacy and safety of CCP-ACI were well maintained at 5-year follow-up.

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Poster Cartilage /Cell Transplantation

P088 - Satisfactory Outcomes After Culture-expanded AD-MSCs Implantation in Knee Focal Cartilage Defects at 6-year Follow-up

Presentation Topic
Cartilage /Cell Transplantation
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The present study aims to evaluate the long-term results of a single-stage cell-based procedure for symptomatic focal cartilage defects in the knee. It was hypothesized that the increased number of autologous AD-MSCs after culture expansion is a safe and efficient cartilage repair procedure, which improves over time chondrogenesis in cartilage lesions

Methods and Materials

Thirty consecutive patients who underwent cartilage repair in the knee with adipose-derived culture-expanded mesenchymal stem cells were prospectively followed for 6 years. To assess functional outcomes patients-reported tools were used including the KOOS and IKDC questionnaires, the Tegner activity scale and the visual analogue scale for pain. Clinical evaluation was quantified by the IKDC examination form. Radiological evaluation of the repair tissue was performed using the MOCART score

Results

All scores recorded a statistically significant improvement (p <0.05) at the final follow-up compared with baseline. The KOOS evaluation showed increased scores in all subcategories. More precisely, KOOS-pain was improved from 62.6 (range 44.0-70.1) to 95.5 (range 92.0-100.0), KOOS-Symptoms from 60.9 (range 46.3-68.0) to96.0 (range 89.0-96.0), KOOS-ADL 60.0 (range 46.8-74.6) to 92.0 (range 87.8-97.0) KOOS-Sports/Rec from 32.5 (range 20.0-45.0) to 70.0 (range 55.0-85.0) and KOOS-QOL from 34.4 (range 23.5-51.5) to 84.5 (range 73.5-88.0). The average IKDC score increased from to 40.2 (range 33.9-49.7) to 76.6 (range 68.4-84.7). Sport activity evaluated using Tegner Activity Score as well as VAS for pain demonstrated the same tendency of significant improvement. MRI findings confirmed complete filling of the defect and integration to the border zone for 68% of the patients. Three patients underwent postoperative biopsies and the histological analysis demonstrated the presence of hyaline-like tissue

Conclusion

Adipose-Derived culture-expanded mesenchymal stem cells were shown to be an efficient and safe single-stage cell-based procedure for symptomatic, full-thickness knee chondral lesions. The findings of the present study demonstrate that all patients presented significant long-term clinical, functional and radiological improvement

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Poster Joint Specific Cartilage Repair

P090 - Results Of Acellular Matrix-Induced Chondrogenesis Tecnique In Chondral Lesions Associated with Femoroacetabular Impingement.

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The study’s main objective was to evaluate, in the short-term, the result of the autologous acellular matrixinduced chondrogenesis (AMIC) technique in a selected group of patients with 2-4 cm2 full-thickness chondral lesions, undergoing hip arthroscopy for femoroacetabular impingement (FAI).

Methods and Materials

A retrospective single-center Level IV case series of 42 patients (49 hips) who underwent an arthroscopic hip surgery with a liquid acellular collagen matrix. Inclusion criteria for implantation were FAI diagnosis, grade IV chondral lesions (Outerbridge size 2-4 cm2); Tönnis stage 0-II, minimum follow-up of 12 months, and 1 year (12-15 months) evaluation with very high field 3-T MRI arthrography. Exclusion criteria were Tönnis III, joint space <2 mm, center-edge angle <20, and <12 months of follow-up. Clinical assessments involved symptoms duration until surgery, mHHS, reporting percentages of patient acceptable symptomatic state (PASS) and minimal clinically important difference (MCID), pain with a VAS, and level of satisfaction. Radiological assessments: Tönnis stage, articular space, alpha and lateral center edge angle (Wiberg), and generated tissue characteristics at 1 year (based on the MOCART score), through 3-T MRI.

Results

42 patients (49 hips) treated; 43 men and 6 women (mean age: 41.5 years; range:25-55). Two women underwent joint replacement surgery. Thus, 40 patients (47 hips) were analyzed. At 36 months following surgery (range: 12-60), improvement was obtained in all parameters assessed, focusing on the characteristics of the generated tissue in the MRI (MOCART scores). 93% of the patients met the MCID (improvement >12 points in the mHHS), and 91% scored >74 points, achieving the PASS. Patients’ satisfaction was 85.6% (SD 20,3).

Conclusion

The liquid AMIC is a safe technique that shows good clinical and radiological outcomes in the short term in patients with femoroacetabular impingement and grade IV acetabular 2-4 cm2 chondral defects.

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Poster Joint Specific Cartilage Repair

P091 - Arthroscopic Bone Marrow Stimulation or Non-Operative Treatment for Osteochondral Lesions of the Tibial Plafond

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The primary purpose of this study was therefore to compare the patient reported outcomes of OLTPs treated with arthroscopic bone marrow stimulation (BMS) and non-operative treatment. The secondary purpose was to compare the reintervention- and complication rates.

Methods and Materials

Patients treated either with BMS (BMS group) or any form of non-operative treatment (Non-operative group) at a minimum follow-up of 12 months were selected from a retrospective database query of patients treated between 1990 and 2020. Patients lost to follow-up/unwilling to participate were excluded for the final analysis. Eligible patients were contacted by phone and cross-sectionally included. The primary outcome was the Numeric Rating Scale (NRS) during weightbearing. Secondary outcomes included; the NRS in rest and the Foot and Ankle Outcome Score (FAOS) Additionally, the reintervention- and complication rates were collected.

Results

table 1.pngA total of 48 patients were included, which consisted of 15 patients for the non-operative group and 33 Patients for the BMS group. See Table 1 for the patient- and lesion baseline characteristics. The median NRS during weightbearing at final follow-up was 2 (IQR: 1-3) for the non-operative group and 1 (IQR: 0-3) for the BMS group (P= 0.17). The NRS in rest, during running, or when climbing stairs was, similarly, not significantly different between groups. None of the FAOS subscales were found to be significantly different between treatment groups. 3 Reoperations in the BMS group were recorded, none for the OLTP, however. No major complications were recorded.

Conclusion

Clinical outcomes following arthroscopic BMS and non-operative treatment yield moderate to good clinical results in this cross-sectional cohort of OLTP patients. This study was the first to report outcomes of non-operative treatment of OLTPs and to compare these to BMS, prospective studies are therefore highly needed for these understudied lesions.

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Poster Joint Specific Cartilage Repair

P092 - Autologous Chondrocyte Implantation in Osteochondral Defects of the Talus: Two to Fourteen Year Follow-up Study

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Autologous chondrocyte implantation (ACI) for treating talar osteochondral defects has given successful results in the short-term. This study aimed to assess survival and functional outcome of chondrocyte implantation techniques at medium to long term follow-up and find predictors of survival.

Methods and Materials

We reviewed the survival until fusion or ankle replacement and functional outcomes of all 63 patients with osteochondral defects (OCD) of the talus managed with three generations of ACI at our Institution between June 1998 and October 2012. Survival was assessed using Kaplan-Meier survival analysis and predictors determined using penalised Cox proportional hazard models. Baseline and followup functional outcome were assessed using the Mazur and AOFAS score and analysed using multilevel models.

Results

The patients (41 male and 22 female) had a mean age of 35.2±10.2SD years at treatment and mean follow-up was 6.3 years (range 1.5-14.6). Mean ankle score increased from 52.6 (95%CI 47.9 to 57.3) preoperatively to 66.9 (95%CI 61.5 to 72.3) at one year (p<0.001), with no evidence of further change (p=0.11). Twelve patients needed ankle fusion or replacement, giving an overall survival of 70% at 10 years and 31% at 15 years (Fig. 1). A bone cyst, no defect on the tibia, no previous surgery and a higher baseline ankle score were associated with lower hazard rates. A prediction model based on these four risk factors had an optimism-corrected concordance of 0.72 and distinguishing four risk levels (0-3) that governed survival until fusion or replacement in our patients.

survplot.png

Conclusion

The results of our study suggest the medium-long term results of ACI for talar osteochondral lesions can be favourable, but that patient selection is important in achieving these results. We produced a risk score that will help patients and surgeons when planning treatment.

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Poster Joint Specific Cartilage Repair

P093 - Autologous Matrix-Induced Chondrogenesis for Isolated Patellar Cartilage Defects: Clinical and MRI Correlation at Two Years of Follow-up

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To correlate the MRI with the clinical outcomes at 2 years of follow-up of patients affected by isolated patellar cartilage defects, ICRS grade 3/4, treated with the AMIC technique. Our hypothesis was that AMIC technique promotes clinical improvement by relieving symptoms, in addition to leading to neocartilage on MRI.

Methods and Materials

From January 2014 to April 2019, 13 patients (16 knees) with symptomatic, isolated patellar chondral defects confirmed by MRI were included. Exclusion criteria were defects < 2cm2, age < 15 years and > 55 years, and patellofemoral or tibiofemoral malalignment. Patients who required additional surgeries were excluded from the study. KOOS, EuroQol-5D, Kujala score and VAS for pain were used as clinical outcomes measures. Diagnosis and follow-up were performed by MRI, using the modified MOCART scale. Statistical data analysis was performed using SPSS (Student Version-Windows 16.0).

Results

Sample: 8 females/5 males, mean age 39.93±8,53 years (range 23-51), mean BMI 27,5 ± 4,71 kg/m2. ICRS grade 4 in 14, grade 3 in one patient. One patient was lost to follow-up. Mean defect surface area 2.63±0.92 cm2 (range 2-4 cm2).

Clinical improvement became statistically significant for VAS (p=0.0001), KOOS (p=0.014), EQ-5D (p=0.0003), and EQ-5D-VAS (p=0.0007). Not statistically significant differences were found for Kujala (p=0.17).

To correlate MRI with clinical results, patients were divided into two groups according to the VAS improvement. There were no significant differences between the two groups in relation to defect filling, cartilage interface, bone interface, integration, bone marrow edema, and surface quality. There were significant differences in signal intensity, structure, subchondral lamina, and osteophyte prevalence.

Conclusion

AMIC presents satisfactory clinical results and promotes neocartilage formation in the medium term, confirmed by MRI, thus fulfilling the hypothesis raised.

Furthermore, it is shown that changes observed on MRI from the baseline to 2 years of follow-up can predict the patient’s clinical outcome.

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Poster Joint Specific Cartilage Repair

P094 - Chondral Resurfacing of Patella in Conjunction with Stabilisation.

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Presentation of results for MACI resurfacing of Patella chondral defects, in association with Trochleaplasty for stabilization of the Patella with a Minimum of 5-year follow-up and to offer a clinical outline of the causes of Patella instability, and the occurrence of Patella chondral injuries.

Methods and Materials

42 Patients who underwent a MACI procedure to a Patellar defect caused by either an acute dislocation/subluxation episode [8], or chronic recurrent instability [34], and a stabilization procedure involving a Trochleaplasty, often together with a Tibial Tubercle Osteotomy, lateral release, and a VMO advancement, were followed for a minimum of a 5 year period and assessed for Patella stability, and subjective symptoms of pain, comfort levels with activities of daily living and return to sports participation, by a VAS score and KOOS Score.

The follow-up was performed by the author, the operating surgeon.

The majority of patients were seen as tertiary referrals and many had undergone prior surgical interventions.

A summary of the clinical and radiological findings guiding the treatment algorithm will be given.

Results

Results will be presented as follows:

A total of 42 patients underwent MACI and trochleaplasty,

Age range 17y to 36 y. Mean age 26y.

1 dislocation,

12 significant stiffness and crepitus, all underwent Arthroscopy, release of adhesions, and often chondroplasty.

3 DVT, anticoagulants.

4 Superficial wound infections, Antibiotics, resolved.

25 TTO,s requiring R/O screw[s], at between 6 to 12 months.

VAS on average reduced from 7 pre-op to 2 at 5 years.

KOOS demonstrated significant improvements in all Parameters, continuing up to the end of the 5 year follow-up.

Conclusion

The combined procedure of MACI chondral resurfacing{grafting} to the patella, together with stabilization by Trochleaplasty offered excellent results for stability{97%}, together with good to very good improvements in pain and function, thus Patella resurfacing should be considered for Patella defects in Patella instability.

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Poster Joint Specific Cartilage Repair

P095 - Functional Medium-term Results of LIPO-AMIC Technique: A 5-year Prospective Cohort Study

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Goal of our study was to assess the clinical, imaging and histologic outcome of LIPO-AMIC technique (autologous matrix-induced chondrogenesis + ADSCs and adipose tissue transfer) consisting of osteochondral lesion debridement, microfracturing and filling with bilayer cell-free collagen scaffold soaked in adipose regenerative product.

Methods and Materials

Eighteen patients (age range: 28-58) with OCL repaired using LIPO-AMIC technique were clinically evaluated through IKDC, KOOS and VAS scores, with follow-up between 12 and 60 months. MRI examinations were performed at 6, 12 months and yearly thereafter. Adipose tissue product used in surgical procedures has been analysed in the laboratory. ADSCs, pericytes, endothelial and progenitor stem cells embedded in the extracellular matrix of the stromal vascular fraction, obtained by mechanical dissociation, have been isolated and characterized in terms of viability and cell composition using multicolor FACS analysis.

Results

No intra or post-op important complications were encountered.
Patients showed relevant, immediate and durature improvement of various scores already from initial follow-up. At intermediate and final follow-up all scores were significantly increased (p<0.001). MRI examination, completed by T2 mapping imaging, showed early subchondral lamina regrowth and progressive maturation of the repair tissue. Histological studies shown that stem cell population resided in a perivascular location with preserved architecture and where ADSCs coexisted with pericytes and endothelial cells. FACS analysis confirmed high viability and a dramatic increased percentage of endothelial cells.

Conclusion

Regenerative repair of full-thickness cartilage injuries by LIPO-AMIC technique provides good to excellent clinical improvement, MRI defect filling and, at histologic evaluation, high percentage of ADSCs and endothelial cell populations with high viability and niche preservation. Results resulted improved in respect to standard AMIC technique and comparable to MACI, at significantly reduced costs.

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Poster Joint Specific Cartilage Repair

P097 - Injectable Scaffold with Microfracture Using the AMIC Technique: A Prospective Cohort Study

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Y.H.L. Dave, Smith and Nephew, Education grant to institution, Speaker fees to individual, Travel grant Y.H.L. Dave, Depuy Mitek, Education grant to institution, Speaker fees to individual, Travel grant Y.H.L. Dave, Arthrex, Speaker fees to individual Y.H

Abstract

Purpose

Autologous matrix-induced chondrogenesis (AMIC) is a one-step surgical cartilage repair procedure involving insertion of a scaffold into the chondral defect after microfracture. BST-CarGel (Smith&Nephew, Watford, England) is an injectable chitosan-based scaffold which can more easily fill defects with irregular shapes and be used to treat vertical or roof chondral lesions. The aim of study is to evaluate the clinical outcomes of knee cartilage repair with microfracture surgery and injectable scaffold BST-CarGel using the AMIC technique at a minimum of 2 years.

Methods and Materials

A prospective study of patients undergoing cartilage repair with microfracture surgery and BST-CarGel at our institution from 2016 to 2019 was performed. Clinical outcomes were determined using two clinically-validated patient-reported questionnaires: Lysholm Knee Scoring System and Knee Injury and Osteoarthritis Outcome Score (KOOS). These questionnaires were administered prior to surgery and at a minimum of two years after surgery.

Results

A total of 21 patients were identified and recruited into the study. 31 cartilage defects were diagnosed and treated in 21 knees. These included horizontal lesions (eg. trochlear, lateral tibial plateau), vertical lesions (eg. medial femoral condyle, lateral femoral condyle) and inverted lesions (eg. patella). No complications or reoperations were seen in our study population. Over an average follow-up of 42.5 ± 8.55 months, there was an average improvement in Lysholm score of 25.8 ± 18.6 and an average improvement in KOOS score of 22.5 ± 15.0.

Conclusion

BST-CarGel with microfracture surgery using the AMIC technique is a safe and effective treatment for cartilage defects in the short to medium term.

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Poster Joint Specific Cartilage Repair

P099 - Long-Term Clinical Results of Arthroscopic Lift-Drill-Fill and Fixation (LDFF) Treatment for Osteochondral Lesions of The Talus

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of this study was to describe the long-term (> 5 year) clinical results of a novel arthroscopic fixation technique for osteochondral lesions of the talus (OLT), named the Lift, Drill, Fill and Fix (LDFF) technique.

Methods and Materials

19 ankles (21 patients) underwent an arthroscopic LDFF procedure for a primary OLT. The mean follow-up was 6.9 years (range: 71.4 - 90.8 months). Pre- and postoperative clinical assessment was prospectively performed by measuring the Numeric Rating Scale (NRS) of pain at rest, during walking and when running. Additionally, the Foot and Ankle Outcome Score (FAOS) including its sub-scores of pain, symptoms, activities of daily living, sports and quality.

Results

The median NRS during weightbearing significantly improved from 7 (IQR: 5 - 8) pre-operatively to 0 (IQR: 0 - 2) post-operatively (p = <0.001), and remained stable from 1-year postoperatively, see Figure 1. The NRS during running significantly improved from 8 (IQR: 6 - 10) to 2 (IQR: 0 - 5) (p < 0.001) and the NRS in rest from 2.5 (IQR: 1 - 3) to 0 (IQR: 0 - 0) (p = <0.001). The median FAOS at final follow-up was 94.4 out of 100 for pain, 71.4 for other symptoms, 98.5 for activities of daily living, 80 for sport and 56.3 for quality of life. The FOAS improved significantly post-operatively on all subscales, expect for the symptoms subscale.ldff.png

Conclusion

Arthroscopic LDFF of a fixable primary OLTs results in excellent pain reduction and improvement of functional outcomes, with sustained results at long-term follow-up. These results indicate surgeons should consider fixation for a fixable OLT.

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Poster Joint Specific Cartilage Repair

P100 - The Arthroscopic Minced Cartilage Technique for the Treatment of Cartilage Defects in the Knee Joint - Is There a Perfect Patient?

Presentation Topic
Joint Specific Cartilage Repair
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The treatment of cartilage has continuously evolved since 1980. The arthroscopic cartilage mincing technique is an open procedure for the one-stage autologous transplantation of cartilage chips, which are fixed with fibrin glue and PRP. Initial studies showed positive results in the short term of up to 12 months. The aim of this study is now to find out whether there are patients who respond best to this surgical procedure and what characterizes these patients.

Methods and Materials

In this study, 100 patients were analyzed and the results were evaluated after 6 months based on 5 criteria - BMI, age, gender, smoker, and insurance type. These criteria were compared using linear multivariate regression and tested for comparability. All patients participated for the first 6 months. The following 5 scores were recorded: VAS, KOOS, KOOS ADL, SANE and Tegner.

Results

In the first 6 months, all patients improved significantly in the KOOS, KOOS ADL and VAS. In the comparison between smokers and non-smokers, there were no differences in all scores 6 months after the intervention. BMI was classified according to WHO criteria (<18.5/18.5-24.9/25.0-29.9/30.0-34.9/35.0-39.9/>40) and showed no difference between groups. Age was categorized into 4 years of life (<29/30-39/40-49/>50) where it can also be seen that there is no difference between the groups. For gender there were also no significant differences between the sexes in all scores. The medians between the two types of insurance in Germany (public-private) are almost identical in the individual scores.

Conclusion

According to our analysis, all patients were highly suitable for autologous minced cartilage joint repair and presented significant improvements in all clinical scores without any differences in the selected subgroups. It is recommended to re-evaluate this analysis after 12 and 24 months and to increase the number of cases.

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Poster Cartilage and Meniscus

P101 - Theranostic Nanoformulation Targets Post Traumatic Osteoarthritis Injuries in the Acute Phase

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Post traumatic osteoarthritis (PTOA) is one of the most common defects of cartilage and a severe cause of disability. After injury, a local inflammatory response results in progressive joint degeneration, and immune cells infiltrate the inflamed synovium (macrophages play an important role in tissue homeostasis). Available treatments still lack effectiveness. Recent studies have shown increasing interest in the use of nanomedicine to develop Drug Delivery Systems (DDSs) for PTOA. Here, we assessed the targeting potential of liposome-based biomimetic nanoparticles (Orthosomes – ORTHO, featuring membranes of macrophages as building blocks) in a PTOA mouse model (dissection of medial meniscus - DMM), during the acute phase of inflammation.

Methods and Materials

Nanoparticles (NPs) were synthesized via thin layer evaporation and extrusion and characterized via dynamic light scattering. Cy7-labeled NPs were administered systemically at 24h, 48h, 72h, and 7d post-injury in a DMM mouse model, and organs and legs were imaged with IVIS.

Results

6h post-NPs administration (size: 100 nm, PDI < 0.15, and surface charge below -40mV), IVIS showed significantly higher accumulation of ORTHO within the injured leg for up to 7 days post-injury. We evaluated NPs’ biodistribution ex vivo: as expected, preferential accumulation of ORTHO occurred in filtering organs, the highest signal being in the liver, kidneys, spleen, lungs. Finally, we qualitatively demonstrated progressive accumulation of NPs in the injury site via intravital microscopy, following the signal of Cy5.5 labeled ORTHO from 15min to 6h post-injection in the DMM group.

Conclusion

Taken together, these findings point towards a revolution of the traditional clinical approaches to treat PTOA: we have demonstrated that these NPs can be used to identify injury sites, fulfilling the need for a diagnostic tool. In addition, the versatility of these DDSs allows them to be potential candidates for encapsulating a variety of drugs, making them a promising theranostic tool for treatment of PTOA.

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Poster Cartilage and Meniscus

P102 - Identification of a Gene Profile for the Meniscus Phenotype From Tissue to Pellet Culture Model

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The meniscus is a fibrocartilaginous tissue comprised of an inner avascular and an outer vascular region. To distinguish it from other mesenchymal tissues, studies have uncovered a set of genes to define the meniscus phenotype. Using the following genes - IGF-BP3, R-Spondin-2, CILP2, CHAD, CSRP2, ID2. Dermatopontin, Collagen XV - we investigated their specificity on meniscus tissue, and on avascular and vascular meniscus cells in monolayer and pellet culture.

Methods and Materials

Human meniscus tissue (n = 3) had a portion snap frozen, whilst remaining tissue was split into avascular and vascular regions for cell isolation. Avascular and vascular meniscus cells were cultured in either a 20% oxygen or 2% oxygen incubator. At passage 1, QIAzol was applied to monolayer cells at each oxygen tension and then frozen. At passage 2, avascular and vascular meniscus pellets were created and cultured for 21 days at each oxygen tension using previously described protocols. RNA was isolated from tissue, cells and pellets using QIAzol method and subsequent qPCR analysis for stated genes was performed using a Biorad CFX96 system.

Results

In meniscus tissue, there was elevated expression levels of all selected genes, with a significant upregulation in CLIP2, CSRP2, Dermatopontin and collagen XV (*p < 0.05). In monolayer, all genes were downregulated, whereas upon pellet redifferentiation, only IGF-BP3, CHAD (*p > 0.05) and Dermatopontin were upregulated in avascular and vascular meniscus cells. There was no significant difference in gene expression with respect to oxygen tension in monolayer and pellets for both meniscus cell types.

Conclusion

The selected genes were all upregulated in meniscus tissue. Monolayer expansion led to downregulation of all genes, whilst subsequent pellet redifferentiation resulted in upregulation of only IGF-BP3, CHAD and Dermatopontin. Future studies should identify optimal in vitro conditions to maintain expression of meniscus-specific genes, thus preventing phenotype drift during cell expansion.

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Poster Cartilage and Meniscus

P105 - An In-silico Method of Evaluating the Effect of Tibial Tubercle Osteotomy on Patellofemoral Cartilage Pressure

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Steven P Mell Navya Dandu Chandhana Voleti Adam Yanke AlloSource Arthrex CONMED Linvatec JRF Olympus Organogenesis PatientIQ Smith & Nephew Sparta Biomedical Vericel Hannah J Lundberg Zimmer

Abstract

Purpose

To generate a semi-automated computational framework for investigating changes in patellofemoral cartilage contact pressure and patellar tracking after AMZ TTO, using subject specific models, dynamic motions, and finite element analysis (FEA) for increased contact pressure accuracy.

Methods and Materials

MRI images from a single patient diagnosed with patellar instability were manually segmented using Mimics (Materialize, NV) into bone and cartilage for the patella and femur, as well as the tibia, quadriceps tendon, and patellar tendon for reference. FEA models were run using Abaqus/Standard 2019 (Dassault Systèmes). The baseline case was native anatomy. Five different surgical scenarios for AMZ TTO were modelled by varying the location of the attachments of the patellar tendon to the tibial tubercle with simulated osteotomy angle cuts of 15, 30, 45, and 60 degrees with translation of 15mm for all conditions. Change in maximum contact pressure on the patella as compared to native anatomy and change in contact path of the center of pressure on the patella and femur were compared for each scenario.

Results

figure 1.jpgContact pressure was greatest for the native anatomy and occurred at 12° of flexion. Maximum contact pressure decreased for all AMZ TTO conditions (15°: 0.58; 30°: 0.86; 45°: 0.60; 60°: 0.62, normalized by native anatomy maximum contact pressure). The path of center of pressure changed subtly for the AMZ TTO conditions with increasing cut angle leading to a more medialized center of pressure at the maximum knee flexion angle and a more superior center of pressure as knee flexion increases during deep squat.

Conclusion

Under all AMZ TTO conditions tested, contact pressure was significantly reduced when compared to the native anatomy. Contact pressure location throughout flexion was similar for the AMZ TTO conditions, however differed from the native anatomy.

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Poster Cartilage and Meniscus

P106 - 3D Printed Meniscal Model for Meniscal Substitution: Study in Rabbits

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To create a three-dimensional meniscus model by robotic impression with PCL enriched with either mesenchymal stem cells or fibrochondrocytes for implantation in rabbits.

Methods and Materials

Fibrochondrocytes (FC) and Mesenchymal Stem Cells (MSC) were harvested from remnants of meniscus and bone marrow of rabbits. Those cells were expanded for 14 days in monolayer, then were seeded on 3D printed meniscus models of polycaprolactone polymer and cultured during 4 days. The meniscus model was generated from Magnetic Resonance Imaging (MRI) data from human meniscus using a scale reduction according with the average of different measurements performed to lateral meniscus of 6 months age rabbits. Meniscal cell-scaffolds were used for partial substitution of lateral meniscus in 6 rabbits. Implants were leave during 12 weeks and new-formed tissue was harvested for histology, inmmunofluorescence, and RNA isolation studies.

Results

snap-121407-0012.jpgfig. 2 3d-meniscus.jpgMeniscal models showed calcein staining of either fibrochondrocytes and mesenchymal stem cells (Fig. 1). In the gross and histological analyses fibrocartilage like tissue was formed in both the FC and MSC groups but with better results in models seeded with fibrochondrocytes (Fig. 2). The presence of Col-1, Agrecane, and Col-2 has better expression in FC scaffolds compared to MSC group that showed osseous tissue formation. A third control acellular group also formed bone tissue as well as expressed RunX2 in RNA.

Conclusion

Is possible to form meniscus like tissue after 12-weeks of lateral 3D-printed meniscal substitution of PCL enriched with fibrochondrocytes

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Poster Cartilage and Meniscus

P108 - The Effect of Increasing Chondral Cartilage Defect Size on Contact Pressure in Human Cadaveric Knees

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of this study is to examine how the tibiofemoral contact pressure is affected by increasing full-thickness chondral defect size on the medial and lateral condyle at full extension.

Methods and Materials

Isolated full-thickness, square chondral defects increasing from 0.09cm2 to 1.0cm2 were created sequentially on the medial and lateral femoral condyles of six human cadaveric knees with intact ligaments and menisci. Defects were created 1.0cm from the femoral notch posteriorly. The knees were fixed to a uniaxial load frame and loaded from 0N to 600N. Contact pressures between the femoral and tibiae condyles were measured using pressure mapping sensors. In post-processing analysis, the peak value for contact pressure was defined as the highest value in the 2.54mm2 area around the defect.

Results

Contact pressures were significantly different between (4.30MPa) 0.09cm2 and (6.91MPa) 1.0cm2 defects (p=0.04) on the medial femoral condyle. On the lateral femoral condyle, post-hoc analysis showed differences in contact pressures between (3.63MPa) 0.09cm2 and (5.81MPa) 1.0cm2 defect sizes (p=0.02).

The location of the stress point shifted from being posteromedial (67% of knees) to anterolateral (83%) after reaching a 0.49cm2 defect size (p < 0.01) in the medial condyle. Conversely, the location of the peak contact pressure point moved from being anterolateral (50%) to a posterolateral (67%) location in defect sizes greater than 0.49cm2 (p < 0.01).icrs2022.png

icrs2022-1.png

Conclusion

Our study suggests that size cutoffs for changing biomechanical parameters exist as small as 0.49cm2 in the natural history of full-thickness chondral defects. These changes in contact area redistribution and cartilage stress in the 0.49 cm2 to 1.0 cm2 range may impact cartilage integrity around the defect in the long term.

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Poster Cartilage and Meniscus

P109 - The Meniscus Punch-out Model – A new Workhorse for Regenerative Meniscus Research?

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

1) Introduce a novel expiremental model and design to study meniscal healing responses to a variety of treatment options, and 2) to present biomechanical and histological baseline data of the model.

Methods and Materials

Human meniscus tissue was obtained from patients undergoing total knee arthroplasty, according to IRB approved protocols. Standardized human menisci with a central defect filled with autologous meniscus tissue were cultured for up to eight weeks without stimulation. Specimens were cut using biopsy punches, the outer ring with an 8 mm biopsy punch, the inner plug with a 4 mm biopsy punch. Meniscus formation and integrity were analyzed at the defect site through 1) biomechanical testing and 2) histology (Safranin O with Haematoxylin counterstain, Picro Sirius Red) and collagen autofluorescence using confocal microscopy. The biomechanical testing was carried out using a static universal test system. The maximal force required to push out the implant from the meniscus rings (Fmax(insert)) was determined using a cylindrical indenter (diameter 3.8 mm).

Results

A total of 92 samples were tested biomechanically and 21 samples histologically. Both biomechanical maximal push out force, as well as histological analysis showed no significant difference between all time points. No significant healing response was visible in the histological images. These results reflect the limited intrinsic healing properties of the human meniscus.

force graph punch out.jpgFigure 1. Force graph of push-out test of a specimen. Force abruptly drops, as soon as inner cylinder is pushed out.

interface.jpg

Figure 2. Collagen autofluoresence image of the punch interface of a simulated 7 days old meniscus tear

Conclusion

The present human meniscus punch model represents a robust, reproducible and highly suitable tool for the long-term culture of meniscus tissue, maintaining matrix integrity and homoeostasis. As an alternative to animal studies, this model may closely reflect early stages of meniscus regeneration/healing, allowing the evaluation of promising regenerative treatment regimes.

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Poster Cartilage and Meniscus

P111 - Robotic Testing of Meniscal Biomechanics In Vitro Validation a Six Degree-of-freedom Robotic System

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

1) Introduce a novel expiremental model and design to induce isolated meniscal tears, 2) to present biomechanical and histological baseline data of the model and 3) to test novel meniscal reconstruction and regeneration methods with the new biomechanical model.

Methods and Materials

A 6 degree-of-freedom robotic arm (HR300 Ultra 2500, Kuka Robotics Corp, Augsburg, Germany) was used in this study. A custom robotic loading profile was created to stress the medial meniscus. The loading profile inludes holding the knee at 60° of flexion while simultaneously applying 1 bodyweight of compression and an internal rotation torque normalized to the specimen’s height and weight. The internal rotation torque was progressively increased from 50% of the normalized value in 10% intervals until significant meniscus damage is present or other knee stabilizing structures fail. The meniscus was visualized and monitored arthroscopically before and after each cycle by a fellowhip-trained orthopedic surgeon.

Results

A total of 3 samples were tested biomechanically. In one specimen a longitudinal tear of the posterior horn of the medial meniscus was induced alongside with an avulsion fracture of the tibial ACL (anterior cruciate ligament) insertion. In a second specimen an isolated radial tear of the meniscal body was induced without concomitant injuries and expanded with subsequent testing. The third specimen, belonging to a 55 year old body donor, sustained a partial tear of the ACL while no meniscal tear was observed.

img_0210.jpeg

Conclusion

Our results validate the use of a robotic system as a testing platform for uniquely stressing the meniscus. The robotic system demonstrated high repeatability during manipulation and superior accuracy. The results of this study will provide an effective means for further determination of native knee biomechanical properties and evaluation of the effect of meniscal pathology and surgical interventions during robotically applied motion cycles. The platform showcases promising potential for further specified meniscal testing.

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Poster Cartilage and Meniscus

P112 - A novel Tissue Engineering Approach for Meniscus Replacement Evaluated Utilising an Ovine Explant Model

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Allografts and synthetic scaffolds made from a proprietary mix of polyurethane and poly-caprolactone (Actifit®) are used clinically as meniscus replacement strategies. Both approaches have shown limited success. The purpose of this study is to assess whether the introduction of autologous cells to commercial scaffolds using a fibrin gel delivery system might improve the synthetic meniscus approach.

Methods and Materials

Medial and lateral menisci were harvested from n=5 sheep. Medial menisci were used to isolate meniscal cells from the avascular region, whilst punch defects (3mm) were created in lateral menisci and cylinders of Actifit® were inserted. Culture expanded avascular meniscal cells with progenitor characteristics were seeded into scaffolds with or without fibrin gel (including an acellular control). The explants were cultured in vitro for 28 days, after which GAG and DNA content were assessed, as well as type I collagen via immunohistochemistry.

Results

Fibrin gel retained cells within the scaffolds and no detachment was observed between the meniscus tissue and scaffold at day 28. In contrast, in the cells without fibrin group, cells were observed streaming out of the scaffold onto plastic and meniscus tissue and scaffold detachment was observed at day 28. GAG and DNA analysis both showed that scaffolds with cells delivered by fibrin gel had higher values for both, compared to the cell only group (figure 1). Histological evaluation confirmed the presence of more collagen I in the fibrin and cells group.

Conclusion

We have demonstrated the feasibility of using fibrin gel to deliver autologous meniscal progenitor cells from the avascular region into a clinical grade meniscus substitute in vitro. Cells delivered by fibrin gel showed increased retention and matrix production within the scaffold compared to cells directly seeded into the scaffold without fibrin. Our data is encouraging for the further development of a novel cell-based tissue engineering approach for meniscus replacement in the clinic.

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Poster Cartilage and Meniscus

P114 - Short-Term Response of Human Meniscus Model to Simulated Microgravity

Presentation Topic
Cartilage and Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Osteoarthritis (OA) is a degenerative disease with much of the focus on knee OA (KOA). As the crucial load-bearing structure, the meniscus is a potential contributor to KOA. The molecular mechanisms regulating the pathogenesis of KOA are poorly understood. However, some characteristics of meniscus fibrochondrocytes (MFCs) from KOA resemble hypertrophic articular chondrocytes undergoing endochondral ossification. We discovered previously that simulated microgravity (SMG) upregulated the expression of hypertrophic markers (COL10A1 and MMP13) of meniscus models developed from human MFCs over several weeks. But the short-term effect was not explored. The aim of this study is to investigate the short-term gene expression profile of human meniscus models exposed to SMG.

Methods and Materials

Human meniscus specimens were procured from 5 males with no history of KOA. Meniscus models were constructed with isolated primary MFCs. The engineered models were cultured under static gravity and SMG conditions for 7 days. Scaffolds were harvested on day 0, 1, 3, and 7, and the expression levels of selected markers were measured by RT-qPCR.

Results

The expression level of the chondrogenic transcription factor SOX9 was comparable in the SMG and static groups on day 1. With prolonged culture, a decrease of expression level in SMG compared to static control was observed. On day 7, SOX9 expression level was 2.2-fold lower. A similar pattern was detected for chondrogenic marker aggrecan (ACAN) and type II collagen (COL2A1). The expression levels were approximately 3-fold lower in the SMG group for both markers on day 7. On the contrary, hypertrophic maker expression level showed continuous upregulation by SMG. On day 7, the type X collagen (COL10A1), matrix metalloproteinase (MMP13), and Indian Hedgehog (IHH) expression levels increased by 1.4-fold, 4.6-fold, and 2.2-fold by SMG, respectively.

smg_static.png

Conclusion

Short-term exposure of meniscus models derived from primary human MFCs to SMG resulted in OA-like gene expression profiles.

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Poster Meniscus

P115 - Return to Play and Player Performance following Meniscus Tear Among Elite Level European Soccer Players

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
O.Lavoie-Gagne, none A. Korrapati, none J. Retzky, none D. Bernstein, Clinical Orthopaedics and Related Research, Editorial board, Institute For Strategy And Competitiveness at Harvard Business School, Employee, Journal of Orthopaedic Experience & Innovat

Abstract

Purpose

Meniscus injuries are extremely common in soccer athletes with little known on post-recovery performance. The purpose of this study was to 1) identify characteristics associated with return-to-play (RTP) to the same league level and 2) evaluate long-term effects injury and management approach may have on player performance.

Methods and Materials

Athletes sustaining meniscal tear were identified across the five major European soccer leagues (English Premier League, Bundesliga, La Liga, Ligue 1, and Serie A) between 2006 and 2016 using publicly available records. Injured athletes were matched to controls 1:2 by demographics and performance. Investigations included rate of RTP to the same league level, re-injury, player characteristics associated with RTP within 2 seasons, long-term availability, field time, and performance metrics standardized to 90 minutes of play during the 4 following seasons.

Results

A total of 250 players sustaining meniscal tear were included, of which 106 (42%) received surgical management. Median absence was 57.5 (IQR 35-92) days or 7 (IQR 4-12) games. Rate of RTP was 70% and the re-injury rate 5% if a player could RTP. Age >30 was a negative predictor for RTP (OR 0.62, p=0.002) whereas higher pre-injury goals per game (OR 2.80, p=0.04) and surgical management (OR 1.38, p=0.002) were positive predictors for RTP. Surgical management was associated with higher long-term availability (p<0.01). As compared to control, there were no significant differences in field time or performance metrics after RTP, either overall or by player position. As compared to nonoperative management, defenders undergoing surgery demonstrated decreased field time. Attackers and midfielders demonstrated similar field time and performance regardless of management.

screen shot 2021-10-15 at 10.16.50 am.png

screen shot 2021-10-15 at 10.17.28 am.png

Conclusion

RTP of elite soccer athletes sustaining meniscal tear is contingent on age, pre-injury performance, and management approach. Those who RTP to the same league level can be expected to demonstrate equivalent field time, performance, and long-term availability as compared to non-injured athletes.

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Poster Meniscus

P116 - Isolated Medial Meniscus Root Tears: An Analysis of Prognostic Variables for Achieving Patient Acceptable Symptomatic State after Repair

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of this study was to describe a cohort of isolated medial meniscus posterior root tears (MMPRTs) and determine short-term clinical outcomes to 1) determine risk factors associated with clinical failures and 2) describe the surgical failure rates.

Methods and Materials

Isolated MMPRT repairs performed 2010-2019 at a single academic institution were reviewed. Clinical failure was defined as patients with International Knee Documentation Committee (IKDC) scores below the Patient Acceptable Symptomatic State (PASS) threshold of 75.9. Surgical failure was defined as root repair re-tear or conversion to arthroplasty. Additionally, pre-MMPRT and final Tegner activity level, pre- and postoperative Visual Analog Scale (VAS) were recorded.

Results

Fifty-one isolated MMPRT repairs (35 females, 16 males, age: 46±12 years, BMI: 31±7 kg/m2) were followed for a mean of 3.1 years (range: 1.2-6.5 years). Mean pre-MMPRT Tegner prior to onset of knee symptoms was 5.1±1.7 and mean immediate preoperative VAS was 4.0±2.7 at rest and 6.0±2.6 with use. Preoperative meniscus extrusion was 3.5±0.9 mm (range: 1.5–5.3). Patients achieved significant postoperative improvements in VAS (p<0.001) and were able to regain Tegner scores of 4.4±1.7, which was statistically similar to their pre-injury levels (p=0.65). At final follow-up, patients with a discrete injury event (HR: 0.39, p=0.02), <4 mm of preoperative extrusion (HR: 2.6 for ≥4 mm extrusion, p=0.03), and preoperative Tegner ≥4 (HR: 0.12, p=0.12) were more likely to meet the IKDC-PASS threshold of 75.9. Two patients (4%) experienced a root repair re-tear, and two patients (4%) converted to arthroplasty at a mean of 4.5 years postoperatively.

Conclusion

Transtibial repair of isolated MMPRTs demonstrates significant improvements in preoperative VAS pain scores and restoration of pre-injury Tegner activity scores. Patients’ ability to achieve a postoperative IKDC-PASS threshold of 74.9 points is predicted by a discrete tear event, preoperative extrusion <4 mm, and high pre-injury activity level.

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Poster Meniscus

P117 - An Analysis of Medial Meniscal Allograft Size Discrepancies Between Patient and Donor Populations

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Recently, specific morphological characteristics of the knee (small medial femoral condyle) have been identified and linked to medial compartment pathology, such as early osteoarthritis (OA). A comparison of anthropometrics and meniscus sizes between medial meniscus allograft transplantation (mMAT) patients and medial meniscus donors might give further insights. We hypothesize that patients with medial pathology are subject to a smaller medial compartment resulting in higher pressures (=force/area).

Methods and Materials

A tissue bank was queried for anthropometrics and medial meniscus size, for both mMAT patient (N=291) and donor (N=1410) pools. The anthropometrics included sex, body mass and height. Two new ratios were introduced: (1) the body mass to meniscus size index (BMMI, kg/cm2) and (2) the height to meniscus index (HMI, cm/cm2) are the ratios of the body mass or height to the estimated meniscus area. Normalising for body mass and height, these ratios allow for comparison independent of anthropometric differences.

Results

Both male and female mMAT patients had a smaller medial meniscus width (p=0.0015) and length (p=0.0001) than donors. The estimated meniscus area was ca. 9% and 8% lower on average for male and female populations (p<0.0001).

In general, patients were more athletically built than donors (Fig. 1): male patients were taller (p=0.0004) and heavier (p=0.0394), while female patients were taller (p=0.008) and lighter (p=0.0166). In the male group, BMMI (p<0.0001; +13%) and HMI (p<0.0001; +9%) were higher for patients versus donors, which is strongly indicating more pressure per surface area unit. As female patients were higher but lighter than donors, BMMI was similar while HMI was significantly higher (p<0.0001; +10%).

morphotype body.jpg

Conclusion

This study confirms that mMAT patients are characterised by a smaller medial compartment. It strengthens the concept that early medial wear and symptoms might be explained by a smaller medial compartment. Future morphology studies might identify post-meniscectomy patients at risk for early medial OA.

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Poster Meniscus

P119 - Defining Clinically Significant Outcomes After Meniscal Allograft Transplantation at Minimum 5-Year Follow-up

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Dr. Cole reports research support from Aesculap/B. Braun, Arthrex, Inc., National Institutes of Health (NIAMS & NICHD), Regentis; Royalties from Arthrex, Inc., Elsevier Publishing, Operative Techniques in Sports Medicine; Stock or Stock Options from Bandg

Abstract

Purpose

To define values and variables predictive for achieving clinically significant outcomes (CSO), including minimal clinically important difference (MCID), substantial clinical benefit (SCB) and patient acceptable symptomatic state (PASS), in patients who underwent meniscal allograft transplant (MAT) at a minimum 5-year follow up.

Methods and Materials

International Knee Documentation Committee (IKDC), Lysholm, and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscales were collected pre-operatively and at most recent follow up for patients who underwent MAT from 1999-2016. A distribution-based approach was used to calculate MCID, while an anchor-based approach was used to calculate SCB and PASS. Logistic regression was performed to determine factors associated with CSO achievement.

Results

102 patients were identified at an average follow-up of 9.7 years (± 3.8 years) and CSO thresholds were determined (Figures 1, 2; Tables 1, 2). Reduced odds of achieving MCID, PASS, and SCB were associated with female sex and increased preoperative scores. Additionally, reduced odds of achieving PASS was associated with worker’s compensation (WC) status, while increased body mass index (BMI) reduced odds of achieving SCB for KOOS Activities of Daily Living (ADL).

Table 1. N=102, binomial variables are presented as frequency. Continuous variables are listed as mean ± SD.
Age at surgery 28.64±9.4
Male sex 47
BMI 25.87±4.2
WC 10
Concomitant Procedures
Osteochondral allograft transplantation 43
Anterior cruciate ligament reconstruction 10
None 27
Table 2. Thresholds for PROMs
MCID
Lysholm 9.5
IKDC 12.0
KOOS
Pain 10.2
Symptoms 11.3
ADL 10.8
Sport 14.8
Quality of Life (QOL) 13.9
PASS
Lysholm 77.0
IKDC 62.6
KOOS
Pain 79.2
Symptoms 62.5
ADL 90.4
Sport 32.5
QOL 46.9
SCB
Lysholm 32.5
IKDC 18.3
KOOS
Pain 15.3
Symptoms 16.1
ADL 13.7
Sport 40.5
QOL 37.2

pass_jk.pngscb_jk.png

Conclusion

At a minimum of 5-year follow-up, female sex, higher preoperative survey scores, increased BMI and WC status are associated with failure to achieve CSOs following MAT.

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Poster Meniscus

P120 - Systematic Review of Medial Meniscus Allograft Transplantation: Surgical Technique, Graft Extrusion and Functional Outcomes

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To systematically summarize the medial meniscus allograft transplantation (MAT) reported outcomes and evaluate whether the surgical technique is associated with allograft extrusion and knee function.

Methods and Materials

In accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a literature review was performed utilizing PubMed, Embase and Cochrane Library databases. Inclusion criteria were English-language clinical studies involving arthroscopically assisted medial MAT that reported the surgical technique as well as the presence of graft extrusion, and/or functional outcomes after surgery. Studies in which the outcomes for medial MAT could not be separated from lateral MAT were excluded. Surgical technique, allograft-related characteristics and clinical outcomes were extracted.

Results

Twenty-five studies were included, the majority of them classified as level of evidence 4 (56%). Of the 335 considered cases of medial MAT, 235 (70.1%) used bone plug technique, 55 (16.4%) bone bridge trough technique, and 45 (13.4%) soft-tissue techniques. Pooled mean value of absolute extrusion after surgery was 3.2 ± 0.9 mm, and the rate of major extrusion (> 3 mm) was 35.8%. Overall, functional scores improved after medial MAT. None of the surgical techniques were associated with poor functional outcomes and extruded meniscus; however, non-anatomically placement of allograft horns increased meniscus extrusion. Graft tear was the most common cause of reoperation (24.4%). Failure rate of 16.7% was demonstrated.

Conclusion

Medial MAT provides favorable outcomes, with acceptable rates of complication and failure regardless of surgical technique. While allograft extrusion appears equivalent for both bone plug and soft-tissue fixation techniques, positioning allograft horns at the native meniscal footprint may be critical for preventing extrusion. However, the heterogeneity and low level of evidence of the studies included in this systematic review prevent decisive conclusions regarding optimal MAT fixation techniques, clinical significance of allograft extrusion, or comparative clinical outcomes after medial MAT.

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Poster Meniscus

P121 - Biomechanical Forces of the Lateral Knee Joint Following Complete Meniscectomy and Subsequent Meniscal Transplant in Pediatric Cadavers

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Meniscus transplantation successfully treats symptomatic meniscal deficiency in children. While clinical outcomes are well characterized, biomechanical lateral joint forces in the meniscus-deficient and transplant states are unknown. We hypothesize that meniscectomy will substantially increase contact pressures and decrease contact area. Transplant will partially restore contact biomechanics of contact pressure and contact area towards normal intact state.

Methods and Materials

Contact area and pressures on lateral tibial plateau were characterized during the intact meniscal state, meniscectomy, and meniscal transplant. Eight cadaver knees (ages 8-12) were tested at robot-controlled degrees of flexion: 0, 30, 60. Tekscan pressure mapping sensors were inserted underneath the lateral meniscus. Meniscus transplant was anchored with transosseous suture fixation and sutured to the joint capsule with horizontal mattresses. Multiple comparisons analysis was performed and Tukey-adjusted p-values are reported.

Results

Contact area of the intact state was significantly greater than meniscectomy state at 0 degrees (p<0.001) and 60 degrees (p=0.059). At 0 degrees, contact area of the intact state was greater than the transplant state (p=0.002) and the transplant state was greater than the meniscectomy state (p=0.026). Compared to meniscectomy state, transplant state at both 30 and 60 degrees improved contact area towards normal, but were non-significant.

Mean and peak pressures of the intact state were significantly less than meniscectomy state at every degree of flexion. Transplant improved mean contact pressures with full restoration of native pressures at 0 degrees and partial restoration at 30 degrees. While transplant did partially improve peak contact pressures at 0 degrees, there were no observed improvements at 30 or 60 degrees. Peak pressures of the transplant state were significantly greater than intact state at 30 degrees (p=0.054) and 60 degrees (p=0.006).transplant_contact.jpgtransplant pressures.jpg

Conclusion

Meniscus transplantation following meniscectomy partially improves contact biomechanics towards normal. Most optimally, contact pressures improve at 0 degrees, whereas mean pressure also improves at 30 degrees. Contact area improves at 0 and 60 degrees.

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Poster Meniscus

P122 - Clinical and T2-mapping Results of Meniscal Substitution with Cellularized Polyurethane Implants: 5-year Follow-up

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To evaluate the clinical results and chondroprotective effect of polyurethane meniscal substitution enhanced with mobilized mesenchymal stem cells versus acellular implants at 48-monthsTo evaluate the clinical results and chondroprotective effect of polyurethane meniscal substitution enhanced with mobilized mesenchymal stem cells versus acellular implants at 48-months

Methods and Materials

Seventeen patients between 18-50 years old with past meniscectomies were enrolled in 2 groups, first, acellular polyurethane scaffold or second one polyurethane scaffold enriched with mesenchymal stem cell. Patients in the cellular group received filgrastim to stimulate mesenchymal stem cells that were harvested and cultured in the polyurethane scaffold during 2 weeks. Then scaffolds were implanted arthroscopically into partial meniscus defects. Concomitant injuries were treated during the same procedure. Changes in the surface of articular cartilage adjacent to the meniscal substitution were evaluated by T2 mapping 60 months with clinical scores as well.

Results

In tibial and femur T2 mapping ROI values for the cellular group were decreased in compared with acellular group at 24 months (P > 0.05) this difference tended to be lower in both groups after 24 months with not significant difference. In the clinical scores, Tegner & KOOS-QOL increased significantly at 12m while Lysholm got better at 18 m (p > 0.05) in the cellular group (Tab.1). The rest of the scales didn`t show significant difference between groups (p > 0.05). Second look at 12-months showed complete integration without rupture or loss of the implant in any group (Fig. 1)

actifit icrs-2022.jpg

tab. 1 actifit.jpg

Conclusion

Polyurethane meniscal scaffolds enhanced with mobilized mesenchymal stem cells shows benefit only the first 24 months, after this time this group does not show any advantage either in the protection of articular cartilage or in clinical scores over acellular scaffolds.

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Poster Meniscus

P124 - Efficacy of Repair, Partial Meniscectomy, & Nonoperative Management of Meniscus Root Tears: A Systematic Review & Network Meta-Regression

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
All authors acknowledge support from the Foderaro-Quattrone Musculoskeletal-Orthopaedic Surgery Research Innovation Fund. CLC personal fees & other from Arhrex, Zimmer Biomet, Stryker Coporation; AJK grants/research funding from Aesculap, B.Braun, Arthrit

Abstract

Purpose

To determine the efficacy of root repair, partial meniscectomy, and nonoperative management in patients with meniscus root tears by performing a network meta-analysis.

Methods and Materials

A systematic review of the literature was conducted in Medline, Scopus, and Embase to identify clinical studies published since 2011 that investigated the efficacy of root repair, partial meniscectomy, and nonoperative management in the treatment of meniscus root tears. Patient cohorts were grouped into treatment categories; data collected included patient demographics, patient-reported outcome measures (PROMs), radiographic outcomes, and progression to total knee arthroplasty (TKA). Interventions were compared via arm-based Bayesian network meta-analysis in a random-effects model.

Results

There was a total of 55 studies that met inclusion criteria with a total of 3191 patients (68.5% female). No studies were of level I or level II evidence. Patient age ranged from 18-83 and mean follow-up time ranged from 18 months to 130 months. Among the studies, 465 patients were nonoperatively managed (14.6%), while 1340 underwent meniscal repair (41.9%), and the remaining underwent meniscectomy (n=1386, 43.4%). Meniscal repair was ranked the highest intervention for both improvements in the IKDC score (effect size = 32, 95% CI: 27-35) and the risk of progression to TKA (relative risk (RR) = 0.07, 95% CI: 0.01-0.35).

figure 1 & 2.jpg

Conclusion

Findings of the network meta-analysis were significantly constrained by heterogeneity. There is a limited amount of evidence to suggest that meniscal repair can produce the greatest improvement on IKDC score and reduce the risk of progression to TKA.

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Poster Meniscus

P125 - The First Clinical Experiences with an Anatomical Medial Meniscus Prosthesis

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
P. Emans, K.DeFoort, and S. vandeGroes are all perform consultancy work for AtroMedical T. van Tienen is foundeer and shareholder of AtroMedical P. Heesterbeek and R. Pikaart were employees of AtroMedical

Abstract

Purpose

There is a strong unmet need for a solution that will relieve post-meniscectomy pain. Purpose of this first-in-man study was to evaluate the safety and clinical performance of an anatomical medial meniscus prosthesis.

Methods and Materials

A first-in-man, prospective, multi-centre, single arm clinical investigation included 5 post-medial meniscectomy syndrome patients with limited underlying cartilage damage and a normal lateral compartment. The polycarbonate urethane medial meniscus prosthesis which was clicked onto two titanium screws fixated at the native horn attachments on the tibia. KOOS was collected at baseline and at 6 weeks, 3, 6, 12 and 24 months and MRI scans at 12 and 24 months.

Results

The surgical technique was demonstrated feasible and reproducable. Positioning of the posterior screw is crucial for correct positioning of the prosthesis. All patients reached the 6 months evaluationon which all patients reported knee joint stiffness and slight effusion. In three patients the implants were removed because of implant failure and in one patient the implant was removed because of persistent pain and extension deficit. In all patients the KOOS score did not improve in the first 6 months after surgery till the implants were removed. The explantations of the implants demonstrated no articular cartilage damage and the fixation screws were securely anchored. One patient still has the implant in situ. In this patient all PROMs started to improve 1 year after surgery and this improvement continued onto 2 years follow up.

Conclusion


This is the first clinical study with an anatomical meniscus prosthesis. One out of five patients showed good clinical results after two years. The other four implants needed to be removed due to failure or discomfort of the patient. Currently the design and surgical technique were changed and will be subject the a first-in-man study.

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Poster Meniscus

P126 - Functional Evaluation and Epidemiology of Meniscal Root Repair with at least 6 Months of follow-up: A Series of Cases

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Purpose: To analyze clinical and functional outcomes of patients submitted to posterior meniscal root repair of the medial or lateral meniscus, with at least 6 months of follow-up.

Methods and Materials

Methods: Retrospective multicentric study, assessing epidemiological characteristics and clinical-functional results of 22 patients who underwent meniscal root reinsertion by transtibial technique.

Results

Results: Twelve had an isolated tear of the posterior root of the medial meniscus and underwent root repair alone. Six patients had a varus axis > 5°, undergoing root repair associated with valgus tibial osteotomy in the same surgical procedure. Four patients underwent repair of the posterior root of the lateral meniscus associated with simultaneous reconstruction of the anterior cruciate ligament. The main results of the study were observed in the improvement of the IKDC score from 27.7% in the preoperative period to 69.8% in the postoperative period (p<0.0001) and the Lysholm score of 44.4 points in the preoperative period to 88.4 points in the postoperative period (p<0.0001). Significant clinical and subjective improvements were also reported.

table 3.png

table 4.png

Conclusion

Meniscal root repair whether isolated or in combination with valgus High Tibial Osteotomy or Anterior Cruciate Ligament reconstruction, when indicated, was able to improve in the short term the clinical, functional and subjective results of the patients presented in this case series. More studies with a high level of evidence and controlled variables are needed to better understand the interventions performed for the treatment of this pathology.

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Poster Meniscus

P127 - Hypermobile Lateral Meniscus: A Case Series Describing Diagnosis and Surgical Outcome

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
BL reports Arthrex, Inc, Smith & Nephew consultancy; Journal of Knee Surgery, KSSTA. Orthopedics Today editorial/governing board; COVR Medical LLC Stock/stock options; Arthrex Inc royalties. AJK reports Arhthrex Inc, Aesculap/B.Braun, Arthritis Foundation

Abstract

Purpose

To report on the demographics, clinical presentation, radiographic features, & surgical outcomes for hypermobile lateral meniscus.

Methods and Materials

Historical & current Mayo Clinic records were queried via MedTagger & Advanced Text Explorer, self-service natural language processing & text-search tools. Results were restricted to records from Rochester MN sites, operated on and cared for between January 1st 2009 to August 19th 2019. Excel (2010; Microsoft Corp, Redmond, WA) preliminary data collection with statistical analyses completed in JMP (v14.1.0, SAS Institute, Cary, NC).

Results

Fourteen patients representing fifteen knees met inclusion criteria. The mean age was 23.9 ± 14.9 years. The majority of the cohort were current athletes (78.5%, 11/14) & had injured the left lateral meniscus (85.7%, 12/14); one patient had bilateral pathology. Only 1 case was correctly identified by radiology on initial MRI. Most repairs utilized all-inside methods (53.3%, 8/15). Average follow-up was 19.73 ± 19.4 months. At final follow-up 78.5% reported complete resolution of pain & mechanical symptoms. All cases with pain or mechanical symptoms at final follow up were secondary to trauma and new injury in the ipsilateral knee. Only 1 patient required revision surgery, while 3 underwent reoperation for new, traumatic pathology, and there were no recorded post-operative complications.

table 1 hmlm icrs.png

table 2 hmlm icrs.png

Conclusion

The hypermobile lateral meniscus continues to be a diagnostic dilemma as previously demonstrated in the literature. These patients may see multiple providers, have imaging studies incorrectly interpreted, and undergo various treatments prior to a successful diagnosis. There are identifiable trends in patient presentation which may lend to a timely, accurate diagnosis and to subsequent surgical intervention with favorable outcomes. This case series, for this rare clinical entity, demonstrates how operative treatment leads to a reliable resolution of mechanical symptoms and pain for patients with a hypermobile lateral meniscus.

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Poster Meniscus

P128 - Clinical results of Ultrasound-guided Intrameniscal Injection of a Solution of Polynucleotides in Degenerative Meniscal Tears.

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Degenerative meniscal tears are common findings even in young patients' knees, and they could be very impacting to everyday quality of life of the patient. Furthermore, standing the high risk of accelerating OA performing meniscectomy in these patients, conservative management is often invoked, even if there is a paucity of therapeutic options. The goal of this study is to evaluate the clinical effect of the ultra-sound guided intrameniscal cycle of three injections of a polynucleotides gel solution, whose viscoelastic properties could let the meniscus regain its shock-proofing role.

Methods and Materials

data regarding 18 patients originally included in the conservative arm of a multicentric nonrandomized clinical trial were included in this paper. A cycle of 3 ultrasound-guided injections of Condrotide® were performed over the course of 2 consecutive weeks. Patients were investigated before the procedure, after 3 months, after 6 months and after 12 months since the last injection. An MRI was performed at basal time and after 6 months. A plan radiograph of the knee was performed at basal time and after 12 months. Symptoms were investigated by KOOS, VAS, IKDC, Tegner score.

Results

18 patients with at least 6 months of follow-up were included.

Mean pre-treatment score were KOOS 54,5 [Symptoms 70; Pain 60; ADL 74,5; Function and Sports 27; QoL 41,5]. Pre-treatment mean VAS was 61. Mean KOOS after three and six months from the completion of the cycle w as 85 and 77,88 [Symptoms 86-96,7; Pain 92-92; ADL 94,5-96; Function and Sports 90; QoL 85,5], VAS was 18,6 at three months and 7 at six months. No adverse reaction were recorded.

Conclusion

Ultrasound-guided intrameniscal injection of Condrotide® showed promising results in providing relief of symptoms in patients with degenerative meniscal tears. Further studies are needed to evaluate the long-term effects of this innovative therapeutic option.

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Poster Meniscus

P129 - 10-years of Clinical Results Patients Treated with a fully Arthroscopic Technique of Collagen Matrix-based Meniscus Repair (AMMR)

Presentation Topic
Meniscus
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The purpose of the present work was to present a long term, 10-year follow-up of clinical results with a fully arthroscopic technique of collagen matrix-based meniscus repair (AMMR) combined with the injection of bone marrow aspirate into the area of the meniscal lesion.

Methods and Materials

53 patients underwent AMMR. The 2-year follow-up period was achieved in 50 cases and a 5 year follow-up – by 44 patients. The present study 23 patients who were available at 10 years. 21 patients who were could not come for a follow-up due to: 11 the Covid-19 pandemic, 4 we lost contact, 6 changed the country of residence. The study group consisted of 6 females (26%) and 17 males (74%). 16 patients underwent an isolated AMMR surgery and in 7 cases AMMR was combined with the ACL reconstruction (AMMR+ACL). The subjective outcomes were evaluated using an form IKDC 2000 and the Lysholm knee scoring scale. WORMS was used to perform the multi-feature, whole-organ assessment of the knee using magnetic resonance images.

Results

The overall results of the WORMS indicated a statistically significant decrease when compared to the 5-year follow-up (p< 0.01) in the group of all patients, as shown in Table 1. Differences were not observed when both subgroups were analyzed separately. Moreover, the difference in the postoperative MRI results for AMMR and AMMR + ACLR groups were not significant at the 10-year follow-up study.

zrzut ekranu 2021-10-22 o 22.33.16.png

zrzut ekranu 2021-10-22 o 22.33.34.png

Improvement in the IKD and the Lysholm scores from the preoperative level to 2 years, 5 years and 10 years of follow-up was observed in all patients.

Conclusion

10 y of observation of patients after the repair of the meniscus by AMMR proves a good treatment result. The stability of the results between 2, 5 and 10 years after treatment allows to think that repairing a meniscal damage in the non-vascular zone is possible.

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Poster Osteoarthritis

P130 - Comparison of Outcomes of Treating Knee Arthrosis with Cultured Adipose Stem Cells or Hyaluronic Acid

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The aim of our study was to compare the effectiveness of treating symptoms of knee arthrosis with cultured adipose stem cell (ADSC) infiltration, and compare them with hyaluronic acid (HA) infiltration. We wanted to check if there is a potential of cartillage regrowth after ADSC infiltration.

Methods and Materials

10 patients with knee arthrosis ICRS grade 3-4 were included in each group and were followed prospectively after the infiltration for 12 months with the VAS scale and the KOOS questionnaire that consists of 5 subscales; Pain, other Symptoms, Function in daily living (ADL), Function in sport and recreation (Sport/Rec) and knee related Quality of life (QOL). From KOOS a KOOS4 score and WOMAC score were calculated. MRI of the knee was performed before and a year after the infiltration. In ADSC group 6 ml of 10 x 106 ADSC, in HA group 6 ml with 60 mg of HA was infiltrated in the knee.

Results

VAS at baseline, at one week, 3 months, 6 months and 1 year was 6.9 (SD 0.9), 3.6 (SD 2.0), 3.1 (SD 3.6), 4 (SD 2.9) and 3.4 (SD 3.7) in ADSC group and 4.6 (SD 2.2), 4.1 (SD 1.8), 4.2 (SD 2.0), 4 (SD 2.3), 4.9 (SD 2.0) in HA group. KOOS4 at baseline, at one week, 3 months, 6 months and 1 year was 33.1 (SD 16.5), 51.9 (SD 12.8), 61 (SD 22.7), 52.9 (SD 21.9), 54.2 (SD 29.7) in ADSC group and 42 (SD 15.5), 42.8 (SD 16.4), 49.6 (SD 16.6), 52 (SD 21.3), 47.6 (SD 16.4) in HA group. MRI has shown cartillage regrowth in a year followup in the ADSC group.

mr prej in potem.jpg

mr prej in potem 2.jpg

Conclusion

HA and ADSC are effective for treating symptoms of arthrosis but ADSC are much more effective and provide an effect even a year after infiltration. Effect on cartillage regrowth with ADSC is possible.

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Poster Osteoarthritis

P131 - Post-Traumatic Osteoarthritis Progression is Diminished by Early Mechanical Unloading and Anti-Inflammatory Treatment in Mice

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
Grant/Research Support - NIAMS/NIH

Abstract

Purpose

Post-traumatic osteoarthritis (PTOA) is a degenerative joint disease that is initiated by a traumatic joint injury. Current treatments during the early phase (<7 days) post-injury aim to reduce pain and inflammation through rest (unloading) and non-steroidal anti-inflammatory drug (NSAID) treatment, but how those early phase interventions impact long-term PTOA progression is unknown. We hypothesized that early unloading and NSAID treatment would both diminish joint inflammation and slow PTOA progression

Methods and Materials

In this study, we use a noninvasive anterior cruciate ligament rupture (ACL-R) mouse model to investigate whether PTOA progression can be slowed with early phase hindlimb unloading (HLU) and/or daily celecoxib (CXB) treatment following ACL-R. Inflammatory protease activity was evaluated using in vivo fluorescence imaging, osteophyte formation and epiphyseal trabecular bone microstructure were quantified using micro-computed tomography, and synovitis and PTOA progression were examined using whole-joint histology at 0, 7, 14, 21, and 28 days post-injury

Results

Hindlimb unloading significantly reduced protease activity and synovitis in injured joints during the unloading period, but these returned to control levels during subsequent reloading. Similarly, trabecular bone volume was partially preserved in injured limbs with HLU, but returned to control values with reloading. Mineralized osteophyte volume was significantly reduced at 21 and 28 days post-injury by both HLU and CXB, but there was not a synergistic effect of these treatments. Similarly, HLU delayed PTOA progression in injured knee joints.

Conclusion

These data suggest that early unloading following a joint injury can diminish inflammation and can potentially have long-term benefits for joint health.

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Poster Osteoarthritis

P132 - The Inflammatory/catabolic “Signature” of IL-1 β Primed sEVs on Osteoarthritis Joint Cells

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship
ICRS Award
Excellence in Cartilage Research

Abstract

Purpose

The last decade has seen growing efforts to exploit the effects of Adipose Derived Stromal Cells (ADSCs) in the treatment of degenerative diseases, including osteoarthritis (OA), and recent findings have suggested that ADSC therapeutic ability is related to paracrine mechanisms. Thus, scientific interest has moved to the ADSC secretome focusing on Small Extracellular Vesicles (sEVs) which can act as “biological drug carriers”. However, the behaviour of sEVs could be affected by ADSC pathophysiology that therefore represents an important issue for clinical application.

The aim of this study was to evaluate the impact of ADSC inflammatory status on their secretome and the effects of the latter on articular tissues, focusing on chondrocytes and synoviocytes derived from OA joints.

Methods and Materials

ADSCs were obtained from adipose tissue harvested during regenerative treatments; chondrocytes and synoviocytes were isolated from tissues collected during knee arthroplasty. sEVs were collected from IL-1β treated ADSC by combining precipitation and size exclusion chromatography. sEVs were quantified, characterized, and administered to chondrocytes/synoviocytes in either monoculture or in co-culture. Gene expression and protein release of cytokines/chemokines, catabolic and inflammatory molecules were analyzed at 4 and 15 h. At the same experimental times, the p65 nuclear translocation was investigated to assess the NF-κB pathway.

Results

figure.jpgFindings of this study demonstrated that the biological effects of ADSC secretome can be affected by the inflammatory environment. IL-1β primed sEVs were able to transfer NF-κB activation to chondrocytes and synoviocytes, inducing the transcription/release of inflammatory chemokines and cytokines, as well as the transcription of major cartilage catabolic enzymes.

Conclusion

Our findings, combined to those we recently published, underline that sEV nature and effects depend on the homeostatic or inflammatory/catabolic status of the ADSC source. Thus, for therapeutic purposes, ADSC should undergo careful characterization to avoid the transfer of an unwanted message that can further promote OA progression.

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Poster Osteoarthritis

P133 - Functionalized Nanogels Decrease Inflammatory and Cartilage Degradation Markers of Osteoarthritis in a Horse Organoid Model of Cartilage

Abstract

Purpose

Horse is a relevant animal model to study osteoarthritis (OA) in human, the main cause of morbidity in developed countries. Human and horse patients both suffer from OA, and no treatment allowing cartilage regeneration currently exists. Among the emerging therapeutic strategies, nanomedicines could efficiently and sustainably deliver drugs in joints. The aim of this project is to develop functionalized nanogels that could improve mechanical functions and protect the cartilage against inflammation and degradation processes. Therefore, two polysaccharidic nanohydrogels (NGs) functionalized with peptides, either an antagonist of endothelin (B) or bradykinin (R) receptors were studied.

Methods and Materials

Equine articular chondrocytes (eACs) cultured as monolayers were incubated with functionalized NGs, alone or combined, to test their biocompatibilities. Secondly, equine cartilage 3D organoids were used to determine the effect of NGs at cellular (eACs phenotype) and tissue levels (eACs environment). To mimic the OA inflammatory context, experiments were performed in the presence of IL-1β.

Results

NGs had no cytotoxic effect, did not alter the eACs viability/proliferation. The combination of both NGs (B+R) decreased the mRNA levels of markers of cartilage extracellular matrix degradation Mmp1, 3, and of inflammation IL-6, -18 and Inos in the organoid model. The nitric oxide (inflammatory mediator) levels and the eACs SA-βgal activity were also downregulated by NGs treatments. Considering matrix components, low expression of type II collagen has been observed at the protein level while that of type I collagen was decreased. Additionally, the NGs (B+R) restricted the downregulation of mRNA levels of hyaline cartilage markers and the upregulation of inflammatory and catabolic markers induced by IL-1β.

Conclusion

Further in vivo studies in horses are required to confirm the in vitro data. Nevertheless, our results strongly suggest that NGs (B+R) could protect cartilage from inflammation and degradation. These NGs could evolve with the addition of a pro-anabolic factor to improve cartilage regeneration.

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Poster Osteoarthritis

P134 - Weight Bearing 3D Models of the Lower Limbs

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The gold standard for preoperative osteotomy planning of the lower limbs requires weight-bearing whole leg radiographs (WLR). However, sagittal and transversal deformities can be overlooked on these 2D images. Additional 3D CT scans can provide this information but lack the weight-bearing aspect. The combination of 3D information with weight-bearing is especially useful in the care of patients presenting knee osteoarthritis with deformities in multiple planes. The aim of this research is to investigate the possibility of creating a weight-bearing 3D model of the lower limbs from a CT scan and a single WLR of the patient (Figure 1).

afbeelding1.png

Methods and Materials

Software was developed for manually aligning 3D models onto a single anteroposterior weight-bearing WLR. This study included 30 patients with available CT scans. Digitally reconstructed (whole leg) radiographs (DRR) and anatomical 3D models were computed from these CT scans. Three raters performed manual registrations of the anatomical 3D models onto the DRRs using the software. The registered 3D models were compared to the 3D models in their original state. Errors were expressed in absolute distances and errors measured in the lower limb geometry: frontal hip knee angle (HKA), sagittal HKA, joint line convergence angle (JLCA), and tibio-femoral rotation.

Results

Mean registration error was highest in the sagittal plane (6.10mm SD ± 4.47mm) compared to the anteroposterior plane (0.89mm SD ± 0.39mm). The angular error was highest for the sagittal HKA and tibio-femoral rotation, respectively 1.63° SD ± 1.28° and 1.69° SD ± 1.33°, and lowest for frontal HKA and the joint line conversion angle, respectively 0.60° SD ± 0.60° and 0.54° SD ± 0.64° (Figure 2).

afbeelding2.png

Conclusion

Manual registration of 3D models onto 2D DRRs provide accurate results in the antero-posterior plane, but results are less accurate in the sagittal plane. This resulted in reliable 3D weight-bearing lower limb models in the frontal plane.

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Poster Osteoarthritis

P135 - Core-fucosylation Deficiency Inhibits Recovery in Early Degenerative Cartilage

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

High-mannose (HM) type N-glycans are known to decrease earlier than histological degeneration and artificial depletion of these glycans causes cartilage degeneration as well as fucosylation of N-glycans (Urita, Homan). However, the effect of fucosylation of N-glycans on cartilage degradation has not been clarified. The purpose of this study was to analyze the effects of fucosyltransferase (α1,6-fucosyltransferase: FUT8) deletion on OA progression.

Methods and Materials

Mice with FUT8 deletion in cartilage-specific type II collagen-expressing cells were generated by crossing mice carrying the fut8 floxed allele to Tg(Col2a1-Cre) mice. Mice were followed for the spontaneous development of OA up to 15 months of age. The femoral head cartilage was cultured for 72 h in serum-free DMEM-plus α-mannosidase. After stimulation, they were returned to complete medium and their recovery from cartilage degeneration was assessed. The expression mode of FUT8 in mouse cartilage N-glycans was confirmed using MALDI-TOF/MS-based high-throughput structural profiling (glycoblotting method).

Results

Cartilage degeneration progressed earlier in aging models of FUT8-deficient mice than in control mice (wild-type and floxed mice) (Figure 1). Enzymatic degradation of HM-glycan on the cartilage in FUT8-deficient mice exacerbated cartilage degeneration. Furthermore, histological cartilage repair after enzyme removal was seen in the control cartilage, but not in FUT8-deficient cartilage. (Figure 2).

figure1 icrs2021.jpg

figure2 icrs2021.jpg

Conclusion

Reduction of HM-glycans in cartilage induced early OA-like degeneration, leading to core-fucosylation of N-glycans. Reversible cartilage degeneration caused by adding α-mannosidase was found to transition to irreversible degeneration by inhibiting the core-fucosylation of N-glycan. These results indicate that the core-fucosylation of glycan structures may be involved in reversible tissue repair in the early stages of cartilage degeneration, and the pathogenesis of early degeneration contributes to the development of OA.

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Poster Osteoarthritis

P136 - Investigation of the Regulatory Pathways Involved in Mesenchymal Stem Cell Mediated Cartilage Repair

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
A patent has been filed to protect some of the findings reported here.

Abstract

Purpose

The chondrogenic capacity of Mesenchymal Stem Cells (MSCs) has led to their use to treat traumatic cartilage injuries. However, these cells have also now been shown to promote tissue repair through the release of cytokines and other regulatory molecules. This trophic effect has opened up the possibility of undifferentiated MSCs being used to treat osteoarthritis (OA). The purpose of this study was to explore differences in regulatory pathways involved in chondrogenesis and in trophic repair.

Methods and Materials

MSCs were cultured from passage 0 until they had become senescent. Cells from sample passages were tested for their potency in a cartilage tissue engineering assay as well as in a meniscal cartilage integration assay as a surrogate for trophic repair. Combined genomic and proteomic screening was used to identify regulatory pathways involved.

Results

Bone marrow derived MSCs from 4 donors were allowed to proliferate until growth arrest. The chondrogenic potency of these MSCs fell significantly with passage. However, there was no reduction in trophic repair. From genomic and proteomic analysis, the largest and most significant change identified in relation to the loss of chondrogenesis with increasing passage was in the cell-cycle master regulator FOXM1 gene pathway, with clear evidence for downregulation of the FOXM1 gene itself and with six out of seven of its downstream effectors also predicted to be downregulated. For trophic repair, which remained high throughout all passages, genes and proteins related to cell movement, cell migration and wound healing also remained at a high level across all four passages, consistent with their involvement in trophic mechanisms.

Conclusion

We have demonstrated clear differences in the regulation of chondrogenic and trophic repair pathways of MSCs, demonstrating that these two mechanisms should be considered as separate and distinct therapeutic opportunities. Further exploration of the pathways invovled may help to optimise each of these therapeutic strategies for the treatment of OA in the future.

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Poster Osteoarthritis

P137 - Progress in Cartilage Cryopreservation Using Nanowarming and Ice-free Vitrification

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
I am an employee and owner of Tissue Testing Technologies LLC.

Abstract

Purpose

Resurfacing of articular cartilage with cold stored osteochondral allografts is employed clinically for repair of trauma and osteoarthritis-induced articular cartilage surface damage. Chondrocyte viability of transplanted articular cartilage is accepted as one of the determinants of outcome following osteochondral allograft transplantation. My team has previously developed an ice-free vitrification method of cryopreservation that maintains excellent chondrocyte viability in small articular cartilage samples. However, it had not previously been possible to rewarm larger samples due to ice nucleation during rewarming that results in loss of chondrocyte viability. The innovation in this presentation relates to a new rewarming method that does not have the limitations of boundary convection warming called nanowarming using magnetic nanoparticles (Figure).nanowarming slide-2.jpg

Methods and Materials

Pig knees were procured post-mortem from Yorkshire cross-farm pigs (~25Kg) at a slaughterhouse. Vitrification was initiated after gradual infiltration with a formulation consisting of 12.6 M of cryoprotectants (4.65M DMSO, 4.65M formamide, and 3.31M 1,2-propanediol in EuroCollins solution) at 4°C. Precooled dilute vitrification solutions were added in sequential steps of increasing concentration on ice. Two mgs/mL Fe magnetic nanoparticles were added in a final step at -10°C. Samples were cooled to -135°C and and stored in a mechanical freezer. Fresh, convection warmed and nanowarmed samples were evaluated by metabolic assay with alternative assays to confirm metabolic activity outcomes. Biomaterial assys were also performed.

Results

Nanowarming by inductive heating system at 500 Amps and 234kHz warmed from -135°C to -30°C in 80 seconds. Longer times and higher settings resulted in overheating and decreased chondrocyte viability. Statistically significant viability (p<0.05) was obtained using nanowarming compared with convection warming using the 12.4M cryoprotectant formulation. Lower cryoprotectant concentrations resulted in dose dependent reductions in viability.

Conclusion

The combination of ice-free cryopreservation by vitrifcation and nanowarming results in the possibility of banking osteocartilage grafts. In vivo porcine studies are in progress.

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Poster Osteoarthritis

P138 - α-MSH Modulates Senescence and Inflammatory State of Human Osteoarthritic Chondrocytes

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Osteoarthritis (OA) is a degenerative joint disease which is closely associated with age. OA causes cartilage loss and structural damage in all joint tissues, with inflammatory mediators playing a critical role. The α-melanocyte–stimulating hormone (α-MSH) is a melanocortin (MC) peptide which mediates its effects via MC receptors (MCR). Beyond pigment induction, α-MSH has several anti-inflammatory and chondro-protective effects mitigating age-related processes. Abrogated MC1R signalling lead to a more severe OA-pathology in a murine surgical OA model. Therefore, the aim of this study was to analyse the effect of α-MSH on senescent human OA chondrocytes.

Methods and Materials

Chondrocytes and synovial fluid (SF) were obtained from OA patients. Chondrocytes, cultivated in 2D monolayers, were incubated with α-MSH and treated with doxorubicin, to induce a senescent phenotype. Induction of senescence was verified by senescence-associated ß-galactosidase (SA-ß-Gal) activity, caspase 3/7 activity and senescence-marker expression. The expression and secretion of pro-inflammatory cytokines and complement markers were analysed in SF, cell lysates and supernatants by qPCR, Western Blot and Multiplex-ELISA. OA chondrocytes were genotyped for MC1R loss-of-function polymorphisms.

Results

We induced SA-ß-Gal expression in all doxorubicin-treated human chondrocytes and did not observe any changes in apoptosis rate. We detected an increase in CDK-inhibitors p16 and p21, as well as increased catabolic markers IL-6, MMP-3, MMP-13, complement components C3, C3a and complement factor B (CFB). Senescent OA chondrocytes incubated with α-MSH showed a decreased inflammatory expression pattern and a reduced secretion of anaphylatoxin C3a in cell supernatants. α-MSH, IL-1ß and IL-6, as well as C3a were altered in SF between OA patients. Different MC1R polymorphisms could be observed in OA samples.

Conclusion

These in vitro data indicated an anti-inflammatory and possibly anti-ageing effect of α-MSH on senescence-induced human osteoarthritic chondrocytes. A correlation between the effect of α-MSH and genetic MC1R variations on OA chondrocyte metabolism needs to be further investigated.

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Poster Osteoarthritis

P140 - Mechanical Forces Enhanced ECM formation and Migratory Behavior of Chondrocytes in Injectable Gels both in Vitro and in Vivo.

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To determine effects of mechanical forces on chondrocytes response using an injectable hydrogel

that can be used to plaster eroded cartilage surfaces and / or to fill up focal cartilage defects.

Methods and Materials

We have develop an injectable hydrogel from naturally occurring polymers such as dextran and HA, that crosslinks under the influence of HRP and H2O2. Using a cartilage-on-chip platform, we determined chondrocyte migratory behavior, viability and catabolic response upon mechanical stimulation after 3 days of culture. The model consist of a mechanical actuation chamber, a 3D cell-hydrogel unit and a perfusion channel to provide nutrients to the structure. Human chondrocytes were embedded in the Dex-HA hydrogel and physiological mechanical stimulation (cell deformation 5-10%) was applied for 1 h x day at 1 Hz. Next, in vivo studies in focal cartilage defect with a duration of 2 weeks and 7 months were performed in an equine joint model.

Results

figure 1 icrs.jpg

Chondrocytes embedded in different ratios of the injectable hydrogel (Dex/HA 5% & 10%) showed migratory behavior upon cyclic mechanical stimuli respect to static conditions and our agarose control in the cartilage-on-chip model. Increased mRNA expression of several catabolic markers (HYAL-1, MMP-1, MMP-3, ADAMTS-4 & -5) was detect at day 3 in mechanically stimulated samples. Nonetheless, chondrocytes did not show significant reduction in viability upon stimulation (Figure 1). The chondrocyte migratory behavior was detected also in the two week horse study. After 7 months the ICRS-II scoring system showed significantly better scores compared to microfracture treatment with presence of chondrocytes within the entire hydrogel.

Conclusion

The outcome of the study suggest that mechanical stimulation enhance catabolic activation and migratory behavior of chondrocytes both in vivo and in vitro. Additionally, the use of the injectable hydrogel enhance the regenerative properties of the cartilage in respect to current procedures.

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Poster Osteoarthritis

P141 - ROR2 Blockade as a Novel Disease-modifying Treatment for Osteoarthritis, Providing Pain Relief and Improved Cartilage Integrity

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Osteoarthritis affects 12% of the population, yet no disease-modifying treatments exist. Cartilage breakdown is the hallmark of osteoarthritis, and patients suffer from pain and loss of joint function/independence, severely affecting quality of life.

Receptor tyrosine kinase–like orphan receptor 2 (ROR2) is a WNT receptor regulating limb outgrowth during development. Chondrocytes require ROR2 to undergo hypertrophy throughout the process of endochondral bone formation. Loss-of-function mutations in humans causes Recessive Robinow Syndrome, characterised by limb shortening and brachydactyly.

Although absent from healthy adult articular cartilage, our studies identified high ROR2 signalling in patients with osteoarthritis, suggesting a role in the disease process.

Aim: To test ROR2 blockade as a novel disease-modifying treatment for osteoarthritis.

Methods and Materials

Human cartilage organoid model, menisco-ligament injury model of osteoarthritis in mice, behavioural studies, in vitro experiments.

Results

ROR2/WNT5A signalling was increased in osteoarthritic cartilage. Blocking ROR2 induced articular chondrogenesis, with anabolic and anti-catabolic effects in a cell line. Human cartilage formation increased in an organoid model in nude mice using primary chondrocytes from patients with osteoarthritis, a clinically validated model that predicts long-term outcome of cartilage repair.

In therapeutic regime, ROR2-siRNA reduced cartilage destruction and provided rapid and sustained pain relief in a murine model of osteoarthritis. Given the limited expression pattern of ROR2 in adulthood, no systemic or local toxicity were expected, nor were any observed (1).

Conclusion

ROR2 blockade has potential as a disease-modifying treatment for osteoarthritis, providing cartilage protection and rapid and sustained pain relief. This will be crucial for clinical success of any treatment for osteoarthritis and promote patient compliance.

Our current approach requires too frequent injections to be acceptable for patients. We are developing longer acting/systemic ROR2 blockers, and researching biomarkers to identify patients with osteoarthritis who are predicted to respond to ROR2-blockade therapy, for patient stratification and individualised therapy.

1. Thorup et al., STM (2020).

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Poster Osteoarthritis

P142 - The Aging Human Hand and Interphalangeal Arthritis Patterns – a Cadaveric Study

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

The movements allowing grasping in the human hand are based on the arch principle. This principle implies that in order to perform proper grasp the so-called stable arch is complimented by the so-called mobile arch in order to complete the force transfer in the human grip.

Human longevity combined with the advent of numerous tasks tackled by the human hand have brought about a rise in osteoarthritis of the hand. The biomechanical and kinetic patterns of force transfer through the human hand have been previously investigated, yet their translation into pathogenesis of osteoarthritis has not been addressed to date.

Methods and Materials

We performed a cadaveric study assessing twelve cadaver hands and 144 digital joints. The hands were meticulously dissected, and the distal articular surface of each joint was photographed in the desired plane and assessed using a software built specifically for arthritic area assessment.

Results

We found a statistically significant difference in radial vs. ulnar pattern of joint arthritis in the proximal interphalangeal joint (PIPJ) of the digits comprising the stable (digits 2 &3) vs. the mobile (digits 3 &4) arch of the hand. Moreover, our findings show that the PIPJ is more prone to arthritis as compared to the metacarpophalangeal joint (MCPJ). Arthritis related to force transfer was more prominent in the more rigid joints.

Conclusion

Our findings corroborate the occurrence of osteoarthritis in the human hand according to grip and grasp patterns. We believe that as the population ages hand osteoarthritis will become more prevalent. The human hand has never, in the history of mankind, survived so long and used so much as in this era. Our study shows arthritis, though apparently inevitable over time, to be tied to force transfer and hand structure after all.

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Poster Osteoarthritis

P144 - Controlled Release of Heavy Chain Only Antibodies Targeting IL-1R to Block IL-1 Signalling

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

Intra-articularly injected biologicals are limited in disease modification by their short in vivo half-life, poor stability and loss of bioactivity. Anakinra, which is a modified recombinant version of IL-1RA is such a therapeutic protein suffering from these limitations. Here, we report a potential alternative for Anakinra, consisting of the variable domain of heavy chain only antibodies (VHHs or nanobodies). The aim is to have a long-term controlled release of bioactive VHH to block IL-1 signaling in the intra-articular space.

Methods and Materials

Several clones of VHHs targeting IL-1R were obtained after immunization of Llama’s, phage library construction and panning rounds. ELISAs and Surface Plasmon Resonance imaging (SPRi) was used to characterize the binding affinity of the VHHs. Bioactivity of the VHHs was determined using a HEK293t cell line stably transfected with an NFκB inducible reporter construct after co-stimulation with IL-1β. As a positive control, a biosimilar of IL-1RA was used. In vitro release studies were carried out using slow release systems composed of various compositions of PCLA-PEG-PCLA triblock co-polymers.

Results

We obtained clones of VHHs targeting IL-1R that had an even higher binding affinity than IL-RA and were more potent than IL-RA in neutralizing Il-1B (fig. 1 and 2). As a next step, these two VHHs were incorporated in slow release systems. Over a time span of 60 days, samples were taken and we observed a sustained release in two compositions. Simultaneously, biological activity was confirmed over time.

icrs2_1.pngicrs.png

Conclusion

We obtained two high affinity IL-1R binding VHHs that could block IL-1 signaling. It is possible to formulate these VHHs in biomaterials for prolonged release without losing biological activity. These VHH formulations are a cost-effective alternative for intra-articular IL-1RA injections.

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Poster Osteoarthritis

P145 - The Grashey True Shoulder AP X-Ray Accurately Reflects Glenohumeral Joint Space and Predicts PRP Efficacy, The Traditional AP Does Neither

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
No Significant Commercial Relationship

Abstract

Purpose

To demonstrate that the shoulder AP view radiograph does not accurately reflect true glenohumeral (GH) joint space narrowing when compared to the Grashey view.

Methods and Materials

A total of 111 patients (122 shoulders) who received evaluation for various shoulder pathologies were included in the study. All patients received baseline Grashey and AP view radiographs. A comparative analysis based on joint space was performed to compare both radiographs of the shoulder. A subgroup of 45 shoulders receiving PRP injection for the treatment of glenohumeral osteoarthritis (GHOA) had previously shown significant efficacy on survivorship, global improvement, SANE and DASH evaluation.

Results

The mean Grashey joint space was 2.8 mm compared to 5.3 mm for the AP joint space. The mean joint space difference between the two views was 2.5 mm (P < 0.0001). Evaluation of the joint space, as measured by AP radiographs, resulted in a 57.4% false negative rate for glenohumeral osteoarthritis. A total of 8 patients received a joint replacement at two year follow up. Of these patients, 7 were in the 0-1 mm Grashey joint space group while only 4 were in the 0-1 mm AP joint space group. There was a 25.3% (p=0.04) difference in the number of responders (≥ 30% Global Improvement) between the 0-1 and 2+ Grashey groups at 6 months follow up. The difference in the number of responders when comparing the AP groups was not statistically significant.

Conclusion

The AP radiograph of the shoulder does not accurately measure, and tends to overestimate, the GH joint space, resulting in a significant amount of false negative GHOA diagnoses. The Grashey view radiograph correlated with clinical outcomes further validating the importance of obtaining an accurate GH joint space, i.e. Grashey radiograph.

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Poster Osteoarthritis

P147 - Risk of Severe Acute Localized Reactions for Different Intra-articular Hyaluronic Acid Kee Injections in a Real World Setting

Presentation Topic
Osteoarthritis
Date
13.04.2022
Lecture Time
09:30 - 09:30
Room
Exhibition Foyer
Session Name
7.3 - Poster Viewing / Coffee Break / Exhibition
Session Type
Poster Session
Disclosure
This study was funded by Sanofi US. For individual author disclosures please email Andrew Gudeman. (list exceeds 500 characters)

Abstract

Purpose

To compare surrogate SALR measures between knee OA patients using hylanG-F 20 and specific non-hylanG-F 20 HA products.

Methods and Materials

Knee OA patients were identified from the Optum Clinformaticsdataset, stratified into hylan G-F 20 and non-hylan G-F 20 HA users, matched by single or multiple injection products.
Surrogate SALR measures within three days of HA use (with ICD/CPT codes): inflammation/infection, intra-articular corticosteroid (CS) injections, arthrocentesis/aspiration, arthrotomy/incision and drainage, arthroscopy, and office visits.

A logistic regression model was used to compare the risk of the surrogate SALR outcomes.

Results

•694,404 HA injections:(Hyalgan/Supartz (35.8%); Euflexxa (24.1%); Orthovisc (17.0%); Synvisc (15.6%); Synvisc-One (6.8%); Gel-One (0.5%); Monovisc (0.2%)).


Multiple injection products:
•Any SALR outcome: similar between hylan G-F 20 (3-injection) and Euflexxa cohorts (p=0.062), except when limited to those with corresponding knee OA diagnoses (AHR=1.24 for hylan G-F 20; p<0.001). Risk lower for hylan G-F 20 (3-injection) than Hyalgan/Supartz (p<0.001) or Orthovisc (p<0.001) patients.

Figure 1. Multiple injection products. * p<0.05; green and red for lower and greater adjusted risks in the hylan G-F 20 (3-injection) group, respectively.

screen shot 2021-10-14 at 11.17.56 am.png


Single injection products:
•Any SALR outcome: lower for hylan G-F 20 (1-injection) than Mo