Purpose

Concomitant application of mononuclear cells (MNCs) or cultured mesenchymal stem cells (MSCs) isolated from bone marrow and seeded on a 3D scaffold could increase the treatment efficacy in patients older than 40 years of age. The aim of our study was to assess two different sources of the bone marrow. Specifically, we compared the material obtained from the proximal tibia with the iliac crest (the commonly used bone marrow source) in terms of quantity and quality of the cells. Comparable features of the biological material would enable us to perform the bone marrow collection from the tibia perioperatively during the arthroscopic surgery. Such strategy would greatly reduce the burden of the patients in the treatment of the chondral lesions.

Methods and Materials

Bone marrow was collected using aspiration biopsy needles from the iliac crest and the proximal metaphysis of the tibia from ten volunteers older than 40 years of age during total knee replacement surgery. MNCs from the obtained material were isolated, cultured and phenotypic analysis was performed. Both sources were compared regarding the yield and viability of the MNCs as well as their ability for chondrogenic differentiation.

Results

The MNCs concentration/yield was significantly higher in the samples from the iliac crests. Similar results were obtained with the cultured MSCs after the first passage when the MSCs/MNCs ratio was compared. Nevertheless, the qualitative analysis that included MSC immuno-phenotyping, viability and population doubling time showed no difference between the two tested bone marrow sources.

Conclusion

The iliac crest represents a superior bone marrow source as for the MNCs and MSCs yield however there was no qualitative difference between the isolated and cultured cells. The population doubling time analysis showed that the tibia is a good alternative source of the MSCs which can be obtained at therapeutically relevant number for the treatment of chondral lesions of the knee.

Purpose

There is a lack of clinical studies comparing the effectiveness of cylindrical autograft and allograft plugs in osteochondral transplantation for the treatment of osteochondral lesions of the talus (OLT). The purpose of this study is to compare the clinical and radiological outcomes of autograft or allograft plug osteochondral transplantation for OLT.

Methods and Materials

A retrospective study comparing outcomes of cylindrical autograft or allograft plug for OLT was performed. After discussion of the risks and benefits of each procedure, the decision in graft choice was made based on patient preference. Clinical outcomes were evaluated using the Foot and Ankle Outcome Score (FAOS) and the Short Form-12 (SF-12) score. MRI was evaluated using Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. The rates of cyst occurrence, graft degradation, graft failure, and revision surgeries were also evaluated.

Results

Twenty-five patients with autograft and 16 with allograft were included, with mean follow-up of 26 months in autograft and 22 months in allograft. There were no significant differences in all demographic variables between the groups. The mean postoperative FAOS and SF-12 were both significantly higher in autograft group than in allograft group (81.9 vs 70.1, p=0.006, 74.7 vs 66.1, p=0.021, respectively). MOCART scores were significantly higher in autograft group (87.1 vs 75.5, p=0.005). The rate of chondral wear on MRI was higher in the allograft group (53% vs 4%, p<0.001). Cyst formation in the graft itself was more likely to occur in allograft (47% vs 8%, p=0.017). The rate of secondary procedures for the graft was higher in the allograft group (25% vs 0%, p=0.009), including 2 nonunions in allograft.

Conclusion

Osteochondral transplantation using cylindrical autograft plug provided better clinical and MRI outcomes than the allograft procedure. The rate of chondral wear on MRI was higher with allograft, and allograft-treated patients had a higher rate of clinical failure.

Purpose

Unicompartmental OA is often characterized by the presence of bone marrow edema (BME) in the femoral condyle and tibial emi-plateau, which is responsible for significant pain. The aim of the present study is to describe the clinical outcome following injection of bone marrow concentrate (BMC) in the articular space and withing the BME areas.

Methods and Materials

Twenty-three patients (15 M and 8W, mean age: 56) were treated by harvesting 90 cc of bone marrow (60cc from the anterior iliac crest and 30cc from the tibia) to achieve 9cc of BMC after centrifugation in the OR. Under fluoroscopic guidance, 3 cc of BMC were injected intra-articularly and in both the BME areas in the femoral condyle and tibial plateau. Patients were prospectively evaluated up to 12 months’ follow-up by the following items: VAS for pain, IKDC subjective and objective, KOOS and Tegner Score. Small samples of BMC obtained from the tibia and the iliac crest were also sent to lab for characterization

Results

No intra-op adverse events has occurred. A significant reduction in VAS for pain was reported at 3 months (from 6.2 ±1.9 to 3.3 ±0.9 ), with stable results up to the final evaluation at one year. Similarly, IKCD-subj. increased from 42.8 ±13.1 to 59.5±15.2 at 3 months, without further statistical improvement up to 12 months. A similar trend was also documented also in all the subscales of KOOS. Two patients were considered failed and underwent other surgical treament. In terms of cellularity, lab analysis revealed significantly higher number of mesenchymal stem cells in the crest-harvested BMC compared to tibia.

Conclusion

Intra-articular and intra-osseous injections of BMC is an easy and safe treatment approach in patients affected by unicompartmental OA associated to BME. Short-term evaluation revealed decrease of pain and improvement in knee function, that should be confirmed at longer follow-up

Purpose

To assess the associations of cell identity (chondrocyte/synoviocyte gene expression ratio) and cell viability assays with patient-reported outcome measures (PROMs), graft survival and repair tissue quality.

Methods and Materials

Seventy-nine patients with a minimum follow-up of 2 years were included in this study. Of these, 67 patients were available for imaging assessment utilizing the MOCART scoring system. Patients were assigned to groups either below or above the cohort’s mean based on individual cell identity score or viability percentage. Detailed statistical analyses were performed to assess the correlation of cell product quality and clinical and imaging outcome, as well as graft survival.

Results

No differences were seen between PROMs within the viability and cell identity groups at a final follow-up of 3.8 ±1.4 years after ACI (p > 0.05). In a subset of patients, the mean MOCART score was 68.3 ±15.6 at an average MRI follow-up of 17.7 ±9.6 months. Cell identity score was statistically correlated with the degree of defect filling (p = 0.025), integration of border zone (p = 0.01), effusion (p = 0.024), and ACI graft survival (p = 0.002). Patients with cell identity scores above the mean (n = 41) had a statistically higher graft survival rate at 5-year follow-up compared to patients with scores below the mean (n = 38) (95.8% vs. 64.7%, p = 0.013). Cell viability did not correlate with MOCART subscales or graft survival (all, p > 0.05). Cell viability and identity showed no significant correlation with each other (r = -0.45; p = 0.694).

Conclusion

Improved repair tissue quality and higher graft survival was associated with a higher individual cell identity score indicating higher chondrocyte/synoviocyte gene expression ratio in the final cell product.

Purpose

In theory, PROMIS instruments allow for improved comparability of outcomes between heterogenous procedures, with decreased question burden and high instrument responsiveness. There is limited information on how PROMIS performs across knee surgical procedures. The purpose of this study was to assess the psychometric properties of PROMIS instruments relative to legacy instruments in anterior cruciate ligament reconstruction (ACLR) and cartilage procedures.

Methods and Materials

PROMIS PF, PI, and Depression CATs were administered alongside legacy instruments in ACLR and cartilage patients. Spearman rank correlations determined correlative strength: >0.8 equated to excellent; 0.71-0.8, very good; 0.61-0.7, good; 0.41-0.6 to fair; 0.21-0.4, poor; <0.20, very poor. Floor and ceiling effects were also evaluated.

Results

PROMIS PF CAT exhibited very poor-good correlations(r=0.01-0.68) in the ACLR cohort and very poor-very good correlations(r=0.14-0.72) in the cartilage cohort relative to function legacies. Legacy HRQoL instruments exhibited fair correlations(r=0.45-0.56) relative to PROMIS PF and PI CAT in ACLR patients, while exhibiting good-very good correlations(r=0.64-0.71) in cartilage patients. The PROMIS Depression CAT performed worse relative to legacy instruments in ACLR patients(r=0.27-0.46) than cartilage patients(r=0.42-0.59). Significant floor effects were demonstrated by the Brief Resilience Scale(15.1%), KOOS Sport(20.5%) and Marx(33.3%). Significant ceiling effects were exhibited by Marx(25.2%), KOOS ADL(25.9%) and all WOMAC scores(22.3%-39.3%).

Conclusion

PROMIS PF and PI CAT correlated well with legacy instruments assessing function and pain in both ACLR and cartilage patients; however, correlation between PF and PI CAT was not as strong for legacy HRQoLs PROMs. Additionally, PROMIS Depression CAT had poor to fair correlations with legacy mental health measures. Significant floor and/or ceiling effects were demonstrated on the Brief Resilience Scale, KOOS Sport, KOOS ADL, Marx and all WOMAC subsets. Neither PROMIS PF, PI, or Depression CAT exhibited any significant floor or ceiling effects. PROMIS PF and PI CATs may allow for comparability of knee surgery procedures while maintaining low questionnaire burden.

Purpose

Osteochondral allograft (OCA) matching remains a challenge that results in surgical delays and potential lesion progression. Studies have demonstrated successful clinical outcomes using nonorthotopic or size mismatched (anterior-posterior [AP] dimension) OCA; however, concerns regarding healing have arisen due to differences in cartilage thickness between the medial and lateral femoral condyles. The purpose of this study was to investigate if osseous mismatch at the OCA and host bone interface resulted in higher reoperation/failure rates when the aforementioned grafts were utilized.

Methods and Materials

We performed a retrospective review of patients treated with a single dowel OCA for a condylar or trochlear defect of the knee between 2011 and 2017. The grafts were obtained from both nonorthotopic and orthotopic (AP size mismatched) sources. The maximum osseous step-off at the OCA and host bone interface was measured using 3T MRI obtained within 11 months post-operatively (Figure 1). Primary outcomes were reoperations and failures, with failure defined by any partial removal/revision of the allograft or conversion to knee arthroplasty.

Results

A total of 39 knees (mean age, 30.5 years) met inclusion criteria.The mean time to post-operative MRI was 6.6 months and mean time to follow-up was 31 months. Maximum osseous step-off ranged from -4.6 mm (recessed) to +4.7 mm (proud), with a mean osseous step-off measuring +1.9 mm. The majority (92%) of OCA chondral surfaces corresponding with the measured osseous locations were flush or <2 mm recessed, with respect to the surrounding host articular surface. There were no significant correlations between maximum osseous step-off (organized by value, magnitude, >2 mm, or proud versus flush/recessed) and reoperation/failure (p>0.31).

Conclusion

Incongruity between the OCA and host bone interface does not result in higher reoperation/failure rates. These findings support previous studies demonstrating satisfactory clinical outcomes when less restrictive graft matching strategies are utilized.

Purpose

To investigate the change of meniscal allografts size, and the changes of intrameniscal signal intensity after MAT according to extrusion.

Methods and Materials

Ninety-one patients who underwent lateral MAT between 2008 and 2013 were retrospectively evaluated by serial magnetic resonance imaging scans 6 weeks, 1 year, and midterm (3- to 7- year) after surgery. Degenerative morphological change was evaluated by postoperative change of meniscal width, thickness, and intrameniscal signal intensity. At each time point, the width and thickness of the menisci at anterior horn, mid-body, and posterior horn were compared between extruded group and extruded group. The ratio of the signal intensity of the transplanted meniscus allograft to that of the control medial meniscus in the ipsilateral knee was calculated to obtain a standardized signal intensity value. The change of signal intensity was evaluated at each part of anterior horn, mid-body, and posterior horn.

Results

Fifty-seven knees (63%) were classified as nonextruded and 34 (37 %) as extruded. Between extruded and nonextruded groups, there was no significant difference in the meniscuscal width, thickness, and signal intensity at anterior horn (p=0.546, p=0.475, and p=0.114, respectively), mid-body(p=0.975, p=0.716, and p=0.415, respectively), and posterior horn(p=0.394, p=0.476, and p=0.420, respectively) during mid-term follow-up. The change of meniscal width and signal intensity did not correlate with Lysholm score. (p>0.5)

Conclusion

After MAT, the meniscus width, thickness, and signal intensity were not related with meniscus extrusion during midterm follow-up. Although overall meniscus width and thickness was decreased after lateral MAT, meniscal extrusion had no effect on the postoperative change of meniscus width, thickness and relative intrameniscal signal intensity during mid-term follow-up. Long-term evaluation is needed to evaluate the natural course of meniscus extrusion after MAT.

Purpose

The Atlas™ system (Moximed Inc.) is a novel implant designed to bridge the treatment gap for medial osteoarthritis between conservative care and joint replacement. The device is placed subcutaneously without violating the joint capsule. A polymer absorber provides an opposing force of up to 142 N to reduce medial compartment loads during weight-bearing. Slynarski observed improved pain and function in patients with medial knee OA. Our aim was to investigate the underlying biomechanical responses to further elucidate the mechanism of action.

Methods and Materials

A CAD model of the Atlas™ was virtually implanted in a validated finite element model based on a 3T MRI of a cadaveric knee. The ideal placement of the femoral and tibial components engaged the absorber during weight-bearing flexion (i.e. <30°) and disengaged the absorber during non-weight-bearing flexion (i.e. >30°). Forces and moments from gait analysis of an anthropometrically matched male were used to drive the model at each sagittal knee angle. Multiple quasi-static simulations were used to analyse the different time-points during stance.

Results

Results were computed as peak values within tibial and femoral cartilage (C-C), and tibial cartilage and meniscus (C-M) contact regions. Medial mean C-C stress reduced by 0.6 ± 0.7 MPa (-45%) while C-M stress reduced by 0.5 ± 0.5 MPa (-46%). Lateral mean C-C stress changed by 0.2 ± 0.3 MPa (-18%), C-M stress remained relatively unchanged (-8%). (Figure 1)

Conclusion

The model demonstrated reduced stress in both medial and lateral compartments, supporting the device's efficacy for unloading the medial tibiofemoral joint, which is consistent with the available clinical data. As medial compartment unloading was not accompanied with an increase in loading of the lateral compartment, we may conclude that the Atlas™ works by sharing as opposed to transferring load. From a biomechanical view, internal joint unloading may work as a treatment for patients unresponsive to conservative care.

Purpose

To evaluate the quality of regenerated cartilage tissue and maturation trend after GelrinC, a hydrogel cartilage repair procedure, using T₂ MRI and texture analysis of T₂ maps.

Methods and Materials

T₂ maps were constructed from multi-echo spin-echo 1.5/3 MR scans and used for Global T₂ index calculation and Texture analysis (grey-level co-occurrence matrix, GLCM).

GLCM analysis was performed on MR scans obtained from fourteen patients, for whom data was available at 18 as well as at 24 months following GelrinC procedure. GLCM texture features, including autocorrelation, contrast, correlation, entropy, dissimilarity and homogeneity were calculated for repaired and native cartilage using selected ROIs of T₂ maps.

Global T₂ index was calculated as a ratio between global T₂ of repaired cartilage and native cartilage at 18 and 24 months following GelrinC implantation respectively.

Differences between repaired and native cartilage for GLCM features and T₂ values were calculated using a paired t-test at the 0.05 significance level.

Results

Global T₂ index values ranging between 0.8 and 1.2 represent healthy cartilage whereas values <0.8 and >1.2 represent fibrotic and disorganized cartilage respectively. The mean global T2 index values at 18 and 24 months were 1.04±0.25 (n=22) and 1.05±0.24 (n=25) respectively, reflecting healthy cartilage.

The 'Autocorrelation' GLCM feature, a measure for cartilage layering, showed significantly different means at 18 and 24 months suggesting development of native stratification of the regenerated tissue. Moreover, the 'Homogeneity' which is a measure of T₂ variation significantly increased between 18 and 24 months, reflecting increased smoothness of the regenerated tissue (Figure 1).

Conclusion

The texture analyses in conjunction with global T₂ values further demonstrates the maturation and organization of the newly regenerated cartilage following GelrinC implantation. Furthermore, the results show that GLCM is a novel and robust method to assess the structure of the repaired cartilage.

Purpose

Microfracture (MFx) has traditionally utilized an awl/mallet technique to stimulate bone marrow healing and growth factor recruitment. A Powerpick drill (Arthrex Inc., Naples, FL, USA) has been introduced as an alternative to traditional methods, although the impact of this new technology on outcomes has yet to be defined. Accordingly, we seek to examine longitudinal outcomes comparing the awl/mallet to the Powerpick technique in MFx surgery.

Methods and Materials

601 patients underwent MFx of the knee at a single institution from 2003-2017. Patient-reported outcome measures (PROMs) consisting of the International Knee Committee Documentation (IKDC) score and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscores were administered at pre-operative, 6 and 12 month timepoints. Operative reports were reviewed for the technique used during MFx surgery, lesion size, and location. Demographic information collected included age, BMI, and surgical history. Student T-tests were performed to analyze differences between groups, as well as across different time points within the same group. MCID achievement utilizing previously established thresholds (IKDC: 11.5) was examined across 6 and 12 months for both groups.

Results

Preoperative, 6 month, and 12 month data was available for a total of 70 patients (32.0±13.1 years, 48.5% female, BMI 26.7±5.3 kg/m²). The average lesion size was 2.27±1.61cm². No statistically significant differences were found in any preoperative PROMs between the awl and Powerpick groups (p>0.32). Statistically significant improvements in all PROMs were seen at both 6 and 12 in the powerpick group(p<0.027), while improvements were not observed in the awl group until 12 months.

Conclusion

Short term data suggest great improvement seen as early as 6 months with respect to sport, MCID, and quality of life when utilizing a Powerpick compared to the traditional awl/mallet microfracture technique. As it was only recently implemented, there is a need to evaluate long-term outcomes in this patient population.