Introduction

The degenerative disease osteoarthritis (OA) is one of the leading causes of disability especially in the Western world. One of the major drivers of OA progression is inflammation, mediated by the secretion of pro-inflammatory cytokines including IL-6, TNF-α and IL-1β by activated chondrocytes or macrophages. Depending on the disease stage, OA treatment involves pharmacological and non-pharmacological approaches, cell-based therapies, or total knee replacement as a last resort. In earlier stages of OA, application of blood derived products including platelet rich plasma (PRP) or the cell-free alternative hyperacute serum (hypACT) gain more and more popularity in regenerative medicine due to their beneficial outcome towards reduced inflammation and promotion of cartilage regeneration. Little is known about the mode of action of these blood derivatives and which of their components are the mediators of their regenerative capacity. Whereas most studies focus on the growth factor content of blood derived products, we aimed to investigate the role extracellular vesicles (EVs) isolated from PRP or hypACT in an inflammation model. EVs are nanosized particles transporting bioactive molecules (mRNA, miRNA, proteins) from one cell to an other resulting in a specific biological response depending on their cargo. We seeked to determine whether these particles are the mediators of blood derived products for cartilage repair.

Content

Materials & Methods

Citrate anticoagulated PRP (CPRP) and hypACT were generated from whole blood according to published protocols involving two-step versus single step centrifugation protocols. OA chondrocytes were obtained from patients undergoing total knee replacement. Primary monocytes obtained from healthy donors as well as the monocytic cell line THP-1 were differentiated and activated into M1 macrophages according to published protocols. A co-culture system of primary OA chondrocytes and activated M1 macrophages was developed to model an OA joint in order to observe the effects of EVs in modulating the inflammatory environment. EVs were isolated by ultracentrifugation and characterized by nanoparticle tracking analysis, cryo-electron microscopy and Western blot. Cytokine secretion of the pro-inflammatory cytokines IL-6, TNF-α and IL-1β within the inflammation model was determined by ELISA.

Results

While mode sizes were similar between EVs from CPRP and hypACT, higher concentrations of EVs were obtained from CPRP compared to hypACT. Western blot analysis confirmed the enrichment of EV markers CD9, CD63 and Alix in P100 fractions after ultracentrifugation. EVs were devoid of buoyant lipoproteins indicated by the absence of ApoB100/48, which is found in (V)LDL particles. EV-supplemented co-cultures showed lower levels of the pro-inflammatory cytokines IL-6, TNF-α and IL-1β compared to co-cultures which were supplemented with the respective blood derivatives from which EVs were isolated.

Conclusion

Compared to the whole blood products CPRP and hypACT, EVs isolated from these blood derivatives were able to decrease the secretion of pro-inflammatory cytokines in a model in which OA chondrocytes were co-cultured with inflammatory M1 macrophages mimicking an OA environment. This highlights the potential of EVs to be one of the main players in mediating the anti-inflammatory effects of blood derivatives which makes them potential candidates for new cell-free therapeutic approaches for OA.

Acknowledgments

This work was jointly supported by the European Fund for Regional Development (EFRE) and the Fund for Economy and Tourism of Lower Austria, frant number WST3-F-5030664/003-2017.

Introduction

no introduction required

Content

Let me share some philosophy and thoughts as a senior surgeon.

Since humans are on this planet teaching was done by the master to the student.

And when techniques were involved, the teaching was also live

Communication was person to person. No alternatives here.

In orthopaedics as in all of surgery learning from the master was the way to go.

“I told you so or I showed you so” was the slogan.

That is how I was trained long ago and appreciated it all the way.

Orthopaedics and trauma treatment are based on a good diagnosis.

The clinical diagnosis that is. Back then no more was around.

History taking was basic and you needed the tricks to get it all out of the patient.

Though I still stick to these principles I see a change in practice towards more technical information more imaging information

Missing what my teachers told me

Masses of information now is made available from new techniques and imaging sources

sometimes with frightening details that scare patient and families

However, missing out on therapeutical impact

And then again

I lived through the origin of arthroscopy and I am staying alive through its technical improvements today

Nevertheless, the abuses on the matter

Too many menisci were removed during last century and this has come around more recently to the benefit for all

But then again too few ACL s were treated at the same time to save the knee

We now know they work together to stabilize the injured knee and prevent degeneration

In the while hypes came up and disappeared again as indeed they are hypes

The likes of double bundle vs single bundle, the existence or not of the ALL, the value of zero alignment or just keep it as it is. And more to come

Good decisions come from experience and good experience comes from bad decisions

The same is true for the diagnosis and the treatment that follows

As experience comes with time and age, share your master s experience and let it reach your students over time

The benefits will be huge to the individual patient but also to the community as this is all we strive for

In Orthopaedics clinical experience is the heart of the matter, imaging may shed some more light on the problem leading to a correct treatment and a satisfied patient pursuing his individual and intimate goals

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References

none

Acknowledgments

to my teachers

to my father who told me to leave this place a better place than when i found it ....................

Introduction

This presentation will focus on my scientist perspective during my post-doctoral research at the University Medical Center Utrecht, The Netherlands.

Content

Part of my highlights consisted of providing academic “meet-the-patient” lectures and making other informative communications with patients¹. These patients participated in an academic driven phase I / II clinical trial that investigated the safety and efficacy of a one-step combination of allogeneic mesenchymal stromal cells (MSCs) and autologous chondrons to treat cartilage defects (IMPACT - NCT02037204)^2-4. A multidisciplinary team consisting of basic scientists, orthopaedic surgeon and researchers with experience in developing and manufacturing advanced therapy medicinal products (ATMPs) took this research from scratch through non- and pre-clinical research to clinical trials^5-7.

In such a multidisciplinary team members speak a different language, have different needs and views and here it is very important to understand each other and to get everyone on the same page. In addition, as a basic scientist, coming from a background in molecular biology, you find yourself in a whole new kind of research area (translational and clinical research). I went from cloning genes to patient reported outcome scores and cost-effectiveness studies. One must want to put in the effort to get to know this new field and also be able to identify opportunities to improve the quality and findings of the research. I enjoyed every part of this challenging and succesful journey and learned so much; not only on doing other types of research but also others skills with a supervisor and other team members with a completely different background.

References

1 https://youtu.be/7cb2cBoY9ro

2 de Windt TS, Vonk LA, Slaper-Cortenbach ICM, Nizak R, van Rijen MHP, Saris DBF. Allogeneic MSCs and Recycled Autologous Chondrons Mixed in a One-Stage Cartilage Cell Transplantion: A First-in-Man Trial in 35 Patients. Stem Cells. 2017 Aug 1;35(8):1984–93.

3 de Windt TS, Vonk LA, Slaper-Cortenbach ICM, van den Broek MPH, Nizak R, van Rijen MHPP, et al. Allogeneic Mesenchymal Stem Cells Stimulate Cartilage Regeneration and Are Safe for Single-Stage Cartilage Repair in Humans upon Mixture with Recycled Autologous Chondrons. Stem Cells. 2017 Jan 1;35(1):256–64.

4 Saris TFF, de Windt TS, Kester EC, Vonk LA, Custers RJH, Saris DBF. Five-Year Outcome of 1-Stage Cell-Based Cartilage Repair Using Recycled Autologous Chondrons and Allogenic Mesenchymal Stromal Cells: A First-in-Human Clinical Trial. Am J Sports Med. 2021;49(4):941–7.

5 Vonk LA, de Windt TS, Kragten AHM, Beekhuizen M, Mastbergen SC, Dhert WJA, et al. Enhanced cell-induced articular cartilage regeneration by chondrons; the influence of joint damage and harvest site. Osteoarthr Cartil. 2014 Nov 1;22(11):1910–7.

6 De Windt TS, Saris DBF, Slaper-Cortenbach ICM, Van Rijen MHP, Gawlitta D, Creemers LB, et al. Direct Cell–Cell Contact with Chondrocytes Is a Key Mechanism in Multipotent Mesenchymal Stromal Cell-Mediated Chondrogenesis. Tissue Eng Part A. 2015 Oct 1;21(19–20):2536–47.

7 Bekkers JEJ, Tsuchida AI, Van Rijen MHP, Vonk LA, Dhert WJA, Creemers LB, et al. Single-stage cell-based cartilage regeneration using a combination of chondrons and mesenchymal stromal cells: Comparison with microfracture. Am J Sports Med. 2013 Sep;41(9):2158–66.

Acknowledgments

As clearly mentioned in the content, this research was part of a multidisciplinary team and as part of that I would line to acknowledge Daniel Saris, Tommy de Windt, Ineke Slaper-Cortenbach, Jasmijn Korpershoek and Roel Custers

Introduction

Hyaline cartilage is a very specialised tissue; it´s main constituents are proteoglycans that attract and retain water and highly organized type II collagen fibers oriented in an arcade like structures. Due to this composition and confirmation, it can transmit mechanical forces and act as a shock absorber¹. In addition, hyaline cartilage has a zonal orientation with the lamina splendens being the uppermost layer. The lamina splendens provides the smooth layer for the smooth movement of articular joints, it is very rich in lubricin and collagen fibers run parallel to the surface of articulation². So, articular cartilage can function due to its composition and their confirmation. This leads to the question whether repairing a cartilage defect is good enough³.

Content

Most of the currently used treatment procedures for cartilage defects do not provide a repair tissue that is similar to the native articular cartilage, or they come with other disadvantages.

For instance for microfracture it is well known that the repair tissue is more fibrocartilage-like that is rich in type I collagen instead of hyaline cartilage-like⁴. Although it provides satisfying outcomes on the short-term, the fibrocartilage cannot take over the function of hyaline cartilage and is more prone to degeneration on the long-term. Therefore, microfracture is only suitable for small defects and in larger defects the initial satisfactory outcomes can decline after a few years⁵. For larger (osteo)chondral defects autologous chondrocyte implantation or osteochondral allografts (if available) or other new upcoming treatments might provide a suitable treatment^6-9. However, also these treatments do not provide 100% success. In addition, the question whether repair is good enough or not is also hampered by the lack of correlation between structural repair (MRI and / or histology) and patient reported outcome measures¹⁰. So even for a set of patients the tissue is repaired with a tissue that is similar to healthy cartilage, but there are still knee problems. On the other hand cartilage damage can be a surprise finding on imaging or during arthroscopy and be asymptomatic¹¹.

References

1. Sophia Fox AJ, Bedi A, Rodeo SA. The basic science of articular cartilage: Structure, composition, and function. Sports Health. 2009;1(6):461–8.

2. Kumar P, Oka M, Toguchida J, Kobayashi M, Uchida E, Nakamura T, Tanaka K: Role of uppermost superficial surface layer of articular cartilage in the lubrication mechanism of joints. J Anat. 2001;199: 241-250.

3. Hunziker EB. The elusive path to cartilage regeneration. Adv Mater. 2009;21:3419–3424.

4. Steadman JR, Briggs KK, Rodrigo JJ, et al. Outcomes of microfracture for traumatic chondral defects of the knee: average 11-year follow-up. Arthroscopy 2003;19:477-84.

5. Mithoefer K, McAdams T, Williams RJ, et al. Clinical efficacy of the microfracture technique for articular cartilage repair in the knee: an evidence-based systematic analysis. Am J Sports Med. 2009;37:2053–2063.

6. Saris DBF, Vanlauwe J, Victor J, Almqvist KF, Verdonk R, Bellemans J. Treatment of Symptomatic Cartilage Defects of the Knee Characterized Chondrocyte Implantation Results in Better Clinical Outcome at 36 Months in a Randomized Trial Compared to Microfracture. Am J Sport Med. 2009;37:10–9.

7. Brittberg M, Recker D, Ilgenfritz J, Saris DBF. Matrix-Applied Characterized Autologous Cultured Chondrocytes Versus Microfracture: Five-Year Follow-up of a Prospective Randomized Trial. Am J Sports Med. 2018;46(6):1343–51.

8. Vonk LA, Roël G, Hernigou J, Kaps C, Hernigou P. Role of Matrix-Associated Autologous Chondrocyte Implantation with Spheroids in the Treatment of Large Chondral Defects in the Knee : A Systematic Review. Int J Mol Sci. 2021;22:7149.

9. Chahla J, Sweet MC, Okoroha KR, et al. Osteochondral Allograft Transplantation in the Patellofemoral Joint: A Systematic Review. Am J Sports Med. 2019;47(12):3009-3018.

10. De Windt TS, Welsch GH, Brittberg M, Vonk LA, Marlovits S, Trattnig S, et al. Is magnetic resonance imaging reliable in predicting clinical outcome after articular cartilage repair of the knee?: A systematic review and meta-analysis. Am J Sports Med. 2013;41:1695–702.

11. Horga LM, Hirschmann AC, Henckel J, et al. Prevalence of abnormal findings in 230 knees of asymptomatic adults using 3.0 T MRI. Skeletal Radiol. 2020;49(9):1099-1107.

Introduction

The success of cartilage repair techniques in the knee joint is multifaceted. A fundamental element to successful clinical outcomes is addressing the causation of the articular cartilage breakdown. Abnormal anatomy and altered biomechanical loading are common factors causing or contributing to cartilage loss in the knee. Such co-pathologies or “background factors” include tibiofemoral malalignment or meniscal deficiency, which exposes a joint compartment to excessive overloading. Altered patellofemoral alignment and kinematics are additional pathological features attributed to cartilage loss. When all causative factors are addressed, even the most advanced cases are amenable to biological repair with good to excellent clinical outcomes.

Content

The success of cartilage repair techniques in the knee joint is multifaceted. A fundamental element to successful clinical outcomes is addressing the causation of the articular cartilage breakdown. Abnormal anatomy and altered biomechanical loading are common factors causing or contributing to cartilage loss in the knee. Such co-pathologies or “background factors” include tibiofemoral malalignment or meniscal deficiency, which exposes a joint compartment to excessive overloading. Altered patellofemoral alignment and kinematics are additional pathological features attributed to cartilage loss. When all causative factors are addressed, even the most advanced cases are amenable to biological repair with good to excellent clinical outcomes.

For example, bipolar or “kissing” lesions in the patellofemoral compartment, a notoriously difficult problem for orthopedic surgeons, can be successfully treated with autologous chondrocyte implantation (ACI) and a concomitant osteotomy, when warranted. A case series of 58 patients (60 knees) who underwent ACI for repair of bipolar patellofemoral lesions demonstrated significant improvement in pain and function, with good survival rates at 5 and 10 years postoperatively (83% and 79%, respectively). Of this cohort, 42 (72%) patients had a corrective osteotomy for either patellofemoral lateral maltracking, patellar instability, or tibiofemoral malalignment. The best survivorship rates were observed among the patients who underwent ACI with a concurrent tibial tubercle osteotomy (TTO). Additional unpublished subcohort analysis demonstrated a 10-year survival rate of 91% when a TTO was performed at the time of ACI using a type I/III bilayer collagen membrane.

Likewise, we showed that ACI for the treatment of symptomatic bipolar cartilage lesions in the tibiofemoral compartments provides successful clinical outcomes in patients at mid- to long-term follow-up. Predisposing risk factors were addressed through concurrent osteotomies in 44 (76%) of the 58 knees. In this series, the survival rate was 80% at 5 years and 76% at 10 years, with significantly higher survival rates in the cohort of patients treated with collagen membrane versus periosteum (97% vs 61% at 5 years, respectively; p = .0014). The patient satisfaction was also high. Of the 46 knees with retained grafts, 91% were satisfied with their outcome, 85% rated their knee as better with the surgery, and 83% rated their outcome as good or excellent at a mean 8.3 years follow-up. At the final follow-up, 24 of the 46 successful knees were radiographically assessed and showed no significant osteoarthritis progression in K-L grading.

Another challenging problem for orthopedic surgeons that can be managed with consideration of the predisposing factors are cartilage lesions in the presence of meniscal deficiency. Our study evaluating 17 symptomatic patients (18 knees) with concomitant cartilage lesions and meniscal deficiency demonstrated 5- and 10-year survival rates of 75% with patient-reported functional improvements at a mean 7.9 years postoperative when meniscal allograft transplantation (MAT) was performed at the time of ACI. Of the cohort, there was no significant osteoarthritic progression using K-L grading from preoperative to mean 5.9 years postoperative. Thirteen patients (76%) maintained their native knee at the final follow-up.

All in all, challenging cases, ranging from bipolar cartilage lesions of the patellofemoral and tibiofemoral joints to cartilage lesions with concurrent meniscal deficiency, can be successfully treated through a means of joint preservation. Careful consideration and management of the causative factors, however, is imperative for good clinical outcomes.

References

Ogura T, Bryant T, Minas T. Biological Knee Reconstruction With Concomitant Autologous Chondrocyte Implantation and Meniscal Allograft Transplantation: Mid- to Long-term Outcomes. Orthop J Sports Med. 2016;4(10):2325967116668490. Published 2016 Oct 19. doi:10.1177/2325967116668490.

Ogura T, Bryant T, Merkely G, Minas T. Autologous Chondrocyte Implantation for Bipolar Chondral Lesions in the Patellofemoral Compartment: Clinical Outcomes at a Mean 9 Years' Follow-up. Am J Sports Med. 2019;47(4):837-846. doi:10.1177/0363546518824600.

Ogura T, Bryant T, Mosier BA, Minas T. Autologous Chondrocyte Implantation for Bipolar Chondral Lesions in the Tibiofemoral Compartment. Am J Sports Med. 2018;46(6):1371-1381. doi:10.1177/0363546518756977.