Sustained superiority in KOOS subscores after matrix-associated chondrocyte implantation using spheroids compared to microfracture

Secondary matrix-associated autologous chondrocyte implantation after failed cartilage repair shows superior results when combined with autologous bone grafting: Findings from the German Cartilage Registry (KnorpelRegister DGOU)

PURPOSE

The aim of this study was to evaluate whether additive autologous bone grafting (ABG) improves clinical outcome and survival in revision matrix-associated autologous chondrocyte implantation (M-ACI) after failed cartilage repair (CR).

METHODS

A retrospective, registry-based, matched-pair analysis was performed to compare patient-reported outcomes and survival in secondary M-ACI with or without additional bone grafting for focal full-thickness cartilage defects of the knee and to compare it with those in primary M-ACI. Patients were matched for age, sex, body mass index, defect size and localization, and number of previous CRs. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was assessed over a follow-up period of 36 months. The patient acceptable symptomatic state, the clinical response rate and the survival of the subgroups were determined.

RESULTS

A total of 818 patients were matched. Revision M-ACI (n = 238) with concomitant bone grafting was associated with significantly higher PRO as measured by KOOS (80.8 ± 16.8 vs. 72.0 ± 17.5, p = 0.032) and higher CRR (81.4% vs. 52.0%, p = 0.018) at 36 months compared to patients with revision M-ACI alone. KOOS and KOOS improvement in these patients did not differ from those who underwent primary M-ACI (p = n.s.). The combination of M-ACI and ABG resulted in a significantly higher KOOS at 36 months than M-ACI alone, regardless of whether bone marrow stimulation (89.6 ± 12.5 vs. 68.1 ± 17.9, p = 0.003) or ACI (82.6 ± 17.0 vs. 72.8 ± 16.0, p = 0.021) was performed before. Additional bone grafting results in equivalent survival rates at 7 years in secondary compared to primary M-ACI (83% vs. 84%, p = n.s.).

CONCLUSIONS

Regardless of the type of previous CR, additional bone grafting in secondary M-ACI improves the clinical outcome, response rate and survival at 36 months compared to M-ACI alone. Secondary M-ACI with ABG had comparable clinical response and survival rates to primary M-ACI. Therefore, subchondral bone should be treated even in cases of mild bone involvement in revision M-ACI.

LEVEL OF EVIDENCE

Level III.

Treatment of Large Cartilage Defects in the Knee by Hydrogel-Based Autologous Chondrocyte Implantation: A 5-Year Follow-Up of a Prospective, Multicenter, Single-Arm Phase III Trial

ObjectiveTo evaluate efficacy and safety at 5 years after treatment with hydrogel-based autologous chondrocyte implantation (ACI) for large cartilage defects in the knee.DesignProspective, multicenter, single-arm, Phase III clinical trial. ACI was performed in 100 patients with focal full-thickness cartilage defects ranging from 4 to 12 cm2 in size. The primary outcome measure was the responder rate (defined as improvement by ≥10 points) at 2 years using the Knee Injury and Osteoarthritis Outcome Score (KOOS).ResultsThe preoperative overall KOOS was 39.8 points and continuously increased to 84.7 points at 5 years (mean increase 44.1 points, 95% CI = 40.4-47.9, P < 0.0001). The primary study endpoint (i.e., a KOOS responder rate of >40%) was descriptively met at each assessment timepoint from 3 months to 5 years (Month 3: 75.5%, 95% CI = 65.6-83.8; Year 2: 93.0%, 95% CI = 86.1-97.1, Year 5: 92.8%, 95% CI = 85.7-97.0). International Knee Documentation Committee (IKDC) subjective and objective scores and quality of life assessments (EQ-5D-5L) supported the results seen for the KOOS. The overall treatment failure rate at 5 years was 1%. All treatment-related adverse events were of mild or moderate intensity and mostly occurred within the first year after treatment.ConclusionsHydrogel-based ACI has been shown to be a safe and effective treatment option for patients with large knee cartilage defects with sustained efficacy up to 5 years as demonstrated by consistent and clinically relevant improvements in all investigated efficacy variables. No remarkable adverse events or safety issues were noted.

Stem and progenitor cells in the synovial joint as targets for regenerative therapy

Damage to articular cartilage, tendons, ligaments and entheses as a result of trauma, degeneration or inflammation in rheumatic diseases is prevalent. Regenerative medicine offers promising strategies for repairing damaged tissues, with the aim of restoring both their structure and function. While these strategies have traditionally relied on tissue engineering approaches using exogenous cells, interventions based on the activation of endogenous repair mechanisms are an attractive alternative. Key to advancing such approaches is a comprehensive understanding of the diversity of the stem and progenitor cells that reside in the adult synovial joint and how they function to repair damaged tissues. Advances in developmental biology have provided a lens through which to understand the origins, identities and functions of these cells, and insights into the roles of stem and progenitor cells in joint tissue repair, as well as their complex relationship with fibroblasts, have emerged. Integration of knowledge obtained through studies using advanced single-cell technologies will be crucial to establishing unified models of cell populations, lineage hierarchies and their molecular regulation. Ultimately, a more complete understanding of how cells repair tissues in adult life will guide the development of innovative pro-regenerative drugs, which are poised to enter clinical practice in musculoskeletal medicine.

Autologous bone grafting combined with spheroid-based matrix-induced autologous chondrocyte implantation for osteochondral defects of the knee: Good clinical outcomes alongside abnormal postoperative gait patterns

PURPOSE

This study aimed to evaluate the clinical and functional outcomes of autologous bone grafting with spheroid-based matrix-induced autologous chondrocyte implantation (MABCI) for osteochondral defects of the knee by analysing pre- and postoperative patient-reported outcome measures (PROMs). Postoperative gait analysis was conducted and compared with a matched healthy control group to investigate biomechanical deviations.

METHODS

A total of 35 patients (m: 21, f: 14; mean defect size: 4.2 ± 2.4 cm², localisation: femoral condyle: 31, patellofemoral: 5) were analysed. The mean follow-up was 42.6 ± 22.8 months. International Knee Documentation Committee (IKDC), Knee Injury and Osteoarthritis Outcome Score (KOOS), PROMIS 29 profile, and a questionnaire on patient perception of treatment success were assessed to evaluate PROMs. 3D-instrumented gait analysis (GRAIL, Motek) was used to assess lower extremity kinematics, kinetics and vertical ground reaction forces, compared to sex-, age- and body mass index-matched healthy controls.

RESULTS

All clinical scores showed significant improvement compared to the preoperative condition (IKDC: 73.1 ± 10.1 vs. 56.6 ± 17.2, p < 0.01; KOOS subcategories: pain 82.0 [±12.7] vs. 70.7 [±16.7] [p < 0.01], symptoms 79.1 [±20.3] vs. 68.9 [±13.9] [p < 0.01], activities of daily living 90.1 [±11.2] vs. 80.5 [±15.6] [p < 0.01], sport and recreational function: 65.3 [±19.3] vs. 51.3 [±26.29] [p < 0.01], quality of life 52.2 [±18.6] vs. 42.6 [±18.6] [p < 0.01]; numeric pain rating scale: 2.7 ± 2.0 vs. 5.0 ± 2.5, p < 0.01). The analysed patients reported a high satisfaction rate (94.3%). Self-selected walking speed was significantly lower than in healthy controls (1.17 ± 0.17 m/s vs. 0.98 ± 0.18 m/s, p < 0.01). Peak knee flexion angle (PKA) during loading response was significantly smaller (9.6° ± 7.0 vs. 17.7° ± 4.6, p < 0.01), and knee extension moment was significantly reduced (0.1 Nm/kg ± 0.2 vs. 0.4 Nm/kg ± 0.2, p < 0.01).

CONCLUSION

MABCI is an effective treatment for osteochondral knee defects, showing significant improvements in all evaluated PROMs. Postoperative gait analysis revealed abnormal gait patterns, including reduced PKA and lower knee extension moment, suggesting a need for further rehabilitation to optimise functional recovery.

LEVEL OF EVIDENCE

Level III.

A prospective randomized controlled trial comparing biphasic cartilage repair implant with microfracture in small chondral lesions of knee: findings at five-year-follow-up

BACKGROUND

Full-thickness cartilage defects have a significant impact on the function of joints in young adults, and the treatment of cartilage defects has been a challenge, as cartilage tissue is an avascular tissue. This study aimed to compare the clinical and radiological outcomes of Biphasic Cartilage Repair Implant (BiCRI) and microfracture treatments for knee cartilage defects.

METHODS

This randomized controlled clinical trial enrolled patients with symptomatic knee chondral lesions smaller than 3 cm2. They were randomized to either the BiCRI (n = 11) or microfracture (n = 10) treatment groups. BiCRI or microfracture surgical procedures were performed on the patients, who were subsequently followed for a period of five years. Primary outcome measures included the International Knee Documentation Committee (IKDC) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), Visual Analog Scale (VAS) score, Magnetic Resonance Imaging (MRI) measured cartilage thickness, and the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score.

RESULTS

21 patients were enrolled, who were subsequently followed for a period of five years. Both BiCRI and microfracture treatments demonstrated significant improvements in IKDC, KOOS and VAS scores, with no significant differences between the two. MRI analysis indicated a significant increase in minimum cartilage thickness with BiCRI treatment (median of difference: 1 mm, P = 0.026)), in contrast to the nonsignificant change in the microfracture group (median of difference: 1 mm, P = 0.102). The MOCART scores revealed a significant increase percentage of isointense signal intensity identical to the adjacent articular cartilage (P = 0.03) in the BiCRI group from the 2-year to the 5-year mark, while the scores remained stable in the microfracture group. Moreover, the BiCRI technique displayed superior performance in graft infill at 5 years (P = 0.008), border integration at 5 years (P = 0.04), surface contour at 2 years (P = 0.04) compared to microfracture.

CONCLUSIONS

Both BiCRI and microfracture treatments showed significant effectiveness in improving clinical outcomes in patients with small symptomatic articular cartilage defects of the knee, with the BiCRI group demonstrating a superior radiological outcome than microfracture, over a five-year period. However, the sample size of our study is relatively small to reach a definite conclusion, and further studies with larger sample size and longer follow up are recommended. Trial registration The trial was registered on ClinicalTrials.gov under the identifier NCT01477008.

Mapping the reporting practices in recent randomised controlled trials published in Knee Surgery, Sports Traumatology, Arthroscopy: A scoping review of methodological quality

The official medical journals of scientific societies advocate for high-quality standards. It's important to assess whether randomized controlled trials (RCTs) in influential journals, such as the hybrid journal of the European Society of Sports Traumatology, Knee Surgery, and Arthroscopy (ESSKA), adhere to reporting guidelines and best practices. Therefore, the present scoping review aimed to explore and map the reporting practices and methodological quality in recent RCTs published in the Knee Surgery, Sports Traumatology, Arthroscopy (KSSTA) journal, focusing on identifying gaps in adherence to reporting guidelines and transparency. The study was preregistered and followed the PRISMA-ScR checklist. RCTs published in KSSTA between 2022 and 2023 were included. The search was conducted via PubMed. A two-stage selection process was employed, with two independent reviewers conducting study selection and data extraction. Data collected included study characteristics, intervention details, sample size calculation reporting, data transparency, and adherence to Consolidated Standards of Reporting Trials (CONSORT) guidelines. Critical appraisal was conducted using the JBI tool for RCTs. All included RCTs (n = 25) reported a predetermined minimum sample size. Study protocol preregistration was reported in 52% of the RCTs, while only 24% provided data availability statements. Most RCTs offering data availability indicated data would be shared upon request. Adherence to CONSORT guidelines was reported in 96% of studies, with only one RCT not adhering to recognized reporting standards. All the included studies adequately addressed statistical conclusion validity. However, internal validity was less consistently addressed across the studies.

Conclusions

While most recently published RCTs in KSSTA adhered to CONSORT guidelines, there is potential for improvement in the reporting of protocol preregistration and data availability statements. Although all studies reported sample size calculations, transparency in data sharing remains limited.

Level of Evidence

Level I.

Biphasic cartilage repair implant versus microfracture in the treatment of focal chondral and osteochondral lesions of the knee: a prospective, multi-center, randomized clinical trial

BACKGROUND

Autologous minced cartilage is a method for cartilage defect repair, and our study focuses on a newly developed biphasic cylindrical osteochondral construct designed for use in human knees. We aimed to compare its clinical effectiveness and safety with microfracture, the commonly utilized reparative treatment for knee chondral or osteochondral defects.

MATERIALS AND METHODS

Conducted as a prospective multicenter, randomized controlled, non-inferiority trial across nine hospitals, the study involved 92 patients with International Cartilage Repair Society (ICRS) grade 3 to 4 chondral or osteochondral lesions on femoral condyles. Patients were evenly randomized to receive either the biphasic cartilage-repair implant (BiCRI) or microfracture. Functional outcomes and safety assessments were conducted at postoperative intervals of 6 weeks and 3, 6, and 12 months. Primary and secondary endpoints included International Knee Documentation Committee (IKDC) 2000 Subjective Knee Evaluation Form score improvement, the grade distribution in the IKDC 2000 Knee Examination Form, and various assessments, such as the Knee Injury and Osteoarthritis Outcome Score (KOOS), visual analog scales (VASs) for pain, MRI findings, and arthroscopic findings at 12 months.

RESULTS

Out of the initial participants, 47 in the BiCRI group and 45 in the microfracture group completed the follow-up. At 12 months, the mean change in IKDC total score was 25.56 ± 18.48 for BiCRI and 27.51 ± 23.65 for microfracture. The 95% confidence interval (CI) for the score difference (BiCRI minus microfracture) was - 6.95, exceeding the non-inferiority margin of - 12. Secondary endpoints indicated comparable functional outcomes, and arthroscopic findings demonstrated more fully regenerated cartilage in the BiCRI group.

CONCLUSION

Based on the IKDC 2000 Subjective Knee Evaluation Form score, BiCRI proved non-inferior to microfracture at 12 months. Short-term functional outcomes were comparable to those with microfracture, while arthroscopic findings showed more complete cartilage regeneration in the BiCRI group. Consequently, BiCRI emerges as a viable alternative for treating chondral or osteochondral defects.

LEVEL OF EVIDENCE

Level 2, multi-center, randomized clinical trial.

TRIAL REGISTRATION

Name of the registry: ClinicalTrials.gov.

TRIAL REGISTRATION NUMBER

NCT01477008. Date of registration: 11/14/2011. URL of trial registry record: clinicaltrials.gov/study/NCT01477008.

Drop in survivorship 13 years after AMIC procedures in aligned knees: A long-term follow-up

PURPOSE

Autologous matrix-induced chondrogenesis (AMIC) showed promising short-term results comparable to microfracture. This study aims to assess the 19-year outcomes of AMIC, addressing the lack of long-term data.

METHODS

Retrospective cohort of 34 knees treated with AMIC underwent a 19-year follow-up. The primary outcome was AMIC survival, considering total knee arthroplasty as a failure event. Survival analysis for factors that were associated with longer survival of the AMIC was also performed. Clinical and radiological outcome scores were analysed for the AMIC group.

RESULTS

Twenty-three knees were available for follow-up analysis. Of these, 14 (61%) underwent revision surgery for total knee arthroplasty (TKA). The mean time was 13.3 ± 2.5 years (range: 9-17 years). Secondary outcomes showed that increased age at surgery (hazard ratio [HR]: 1.05; p = 0.021) and larger defect size (HR: 1.95; p = 0.018) were risk factors for failure. Concomitant proximal tibial osteotomy (HR: 0.22; p = 0.019) was associated with longer survival. The remaining nine knees (39%) were analysed as a single group. The mean clinical score at follow-up of 18.6 ± 0.9 SD years was 79.5 ± 19.7 SD for the Lysholm score, 1.8 ± 1.5 SD for the visual analog scale score, 74.2 ± 22.4 SD for the KOOS score and a median of 3 (range: 3-4) for the Tegner activity scale.

CONCLUSIONS

The mean survival time of 13.3 years indicates the durability of AMIC in properly aligned knees. Nonetheless, despite a 61% conversion to TKA, the knees that persisted until the 19-year follow-up remained stable, underscoring the procedure's longevity and consistent clinical outcomes.

LEVEL OF EVIDENCE

Level IV.

Commercial Insurance Coverage Criteria for Autologous Chondrocyte Implantation Poorly Reflect Current Research

OBJECTIVE

The aim of this study is to both quantify and qualify the way insurance companies justify their coverage policies for autologous chondrocyte implantation (ACI) and determine whether these policies align with recent research on the subject.

DESIGN

The top 11 national commercial health insurance payers for ACI were identified. Coverage policy documents were recovered for 8 payers. These documents were examined, and the type of reference and the level of evidence (LOE) were recorded for each applicable reference. Specific coverage criteria for each individual payer were then extracted and assessed for similarities among commercial payers. Finally, all references cited by each payer were examined to determine whether they mentioned the specific payer criteria.

RESULTS

This study found that the majority of cited references were primary journal articles (86, 58.1%) and that only 30 (20.2%) references were level I or level II evidence. This study also found significant homogeneity among payer coverage criteria. Cited sources inconsistently mentioned specific payer coverage criteria. In addition, payer criteria tended to be poorly supported by current evidence on ACI.

CONCLUSIONS

This study demonstrates that commercial insurance payers' coverage policies for ACI poorly cite references, cite a majority of references with low LOE, and cite references which infrequently mention their specific coverage criteria. In addition, payer coverage policies have a high degree of homogeneity and many of their specific criteria are poorly supported by current research on ACI.

Hydrogel-based and spheroid-based autologous chondrocyte implantation of the knee show similar 2-year functional outcomes: An analysis based on the German Cartilage Registry (KnorpelRegister DGOU)

PURPOSE

To compare short-term patient-reported outcomes (PRO) of two contemporary matrix-associated autologous chondrocyte implantation (M-ACI) products for the treatment of large articular cartilage defects of the knee.

METHODS

A retrospective, registry-based, matched-pair analysis was performed, comparing PRO of patients undergoing isolated M-ACI with either Spherox™, a spheroid-based ACI (Sb-ACI), or NOVOCART™ Inject, a hydrogel-based ACI product (Hb-ACI), for a focal full-thickness cartilage defect of the knee ≥4 cm2. Matching parameters included age, sex, body mass index, defect size, defect localization, symptom duration and previous surgeries. The Knee Injury and Osteoarthritis Outcome Score (KOOS) and the International Knee Documentation Committee (IKDC) score were obtained up to the 24-month follow-up. The total KOOS response rate and percentage of patients attaining a substantial clinical benefit (SCB) in KOOS subscores were calculated.

RESULTS

A total of 45 patients per group were matched. The response rate after 24 months was not significantly different between the groups (Sb-ACI 64.4% vs. Hb-ACI 82.2%, p = 0.057). The number of patients with a SCB at 24 months was not significantly different in any KOOS subscore, despite significantly higher improvement of the total KOOS (14.8 ± 16.2 vs. 21.5 ± 15.4, p = 0.047) and KOOS pain in the Hb-ACI group (12.2 ± 18.6 vs. 20.6 ± 19.1, p = 0.037). The IKDC score in the Hb-ACI group was significantly higher at the 12- and 24-month follow-up (60.7 ± 20.2 vs. 70.9 ± 18.0, p = 0.013).

CONCLUSION

The response rate and number of patients achieving an SCB were not significantly different between patients treated with Sb-ACI or Hb-ACI. Both procedures can achieve favourable 2-year PRO. Hb-ACI was associated with better PRO between 1 and 2 years postoperatively; however, the clinical relevance of this benefit is yet to be proven.

LEVEL OF EVIDENCE

III, Retrospective comparative study.

Knee Cartilage Lesion Management-Current Trends in Clinical Practice

Many patients, particularly those aged above 40, experience knee joint pain, which hampers both sports activities and daily living. Treating isolated chondral and osteochondral defects in the knee poses a significant clinical challenge, particularly in younger patients who are not typically recommended partial or total knee arthroplasty as alternatives. Several surgical approaches have been developed to address focal cartilage defects. The treatment strategies are characterized as palliation (e.g., chondroplasty and debridement), repair (e.g., drilling and microfracture), or restoration (e.g., autologous chondrocyte implantation, osteochondral autograft, and osteochondral allograft). This review offers an overview of the commonly employed clinical methods for treating articular cartilage defects, with a specific focus on the clinical trials conducted in the last decade. Our study reveals that, currently, no single technology fully meets the essential requirements for effective cartilage healing while remaining easily applicable during surgical procedures. Nevertheless, numerous methods are available, and the choice of treatment should consider factors such as the location and size of the cartilage lesion, patient preferences, and whether it is chondral or osteochondral in nature. Promising directions for the future include tissue engineering, stem cell therapies, and the development of pre-formed scaffolds from hyaline cartilage, offering hope for improved outcomes.

Autologous and Allogeneic Cytotherapies for Large Knee (Osteo)Chondral Defects: Manufacturing Process Benchmarking and Parallel Functional Qualification

Cytotherapies are often necessary for the management of symptomatic large knee (osteo)-chondral defects. While autologous chondrocyte implantation (ACI) has been clinically used for 30 years, allogeneic cells (clinical-grade FE002 primary chondroprogenitors) have been investigated in translational settings (Swiss progenitor cell transplantation program). The aim of this study was to comparatively assess autologous and allogeneic approaches (quality, safety, functional attributes) to cell-based knee chondrotherapies developed for clinical use. Protocol benchmarking from a manufacturing process and control viewpoint enabled us to highlight the respective advantages and risks. Safety data (telomerase and soft agarose colony formation assays, high passage cell senescence) and risk analyses were reported for the allogeneic FE002 cellular active substance in preparation for an autologous to allogeneic clinical protocol transposition. Validation results on autologous bioengineered grafts (autologous chondrocyte-bearing Chondro-Gide scaffolds) confirmed significant chondrogenic induction (COL2 and ACAN upregulation, extracellular matrix synthesis) after 2 weeks of co-culture. Allogeneic grafts (bearing FE002 primary chondroprogenitors) displayed comparable endpoint quality and functionality attributes. Parameters of translational relevance (transport medium, finished product suturability) were validated for the allogeneic protocol. Notably, the process-based benchmarking of both approaches highlighted the key advantages of allogeneic FE002 cell-bearing grafts (reduced cellular variability, enhanced process standardization, rationalized logistical and clinical pathways). Overall, this study built on our robust knowledge and local experience with ACI (long-term safety and efficacy), setting an appropriate standard for further clinical investigations into allogeneic progenitor cell-based orthopedic protocols.

Hyperplastic Human Macromass Cartilage for Joint Regeneration

Cartilage damage affects millions of people worldwide. Tissue engineering strategies hold the promise to provide off-the-shelf cartilage analogs for tissue transplantation in cartilage repair. However, current strategies hardly generate sufficient grafts, as tissues cannot maintain size growth and cartilaginous phenotypes simultaneously. Herein, a step-wise strategy is developed for fabricating expandable human macromass cartilage (macro-cartilage) in a 3D condition by employing human polydactyly chondrocytes and a screen-defined serum-free customized culture (CC). CC-induced chondrocytes demonstrate improved cell plasticity, expressing chondrogenic biomarkers after a 14.59-times expansion. Crucially, CC-chondrocytes form large-size cartilage tissues with average diameters of 3.25 ± 0.05 mm, exhibiting abundant homogenous matrix and intact structure without a necrotic core. Compared with typical culture, the cell yield in CC increases 2.57 times, and the expression of cartilage marker collagen type II increases 4.70 times. Transcriptomics reveal that this step-wise culture drives a proliferation-to-differentiation process through an intermediate plastic stage, and CC-chondrocytes undergo a chondral lineage-specific differentiation with an activated metabolism. Animal studies show that CC macro-cartilage maintains a hyaline-like cartilage phenotype in vivo and significantly promotes the healing of large cartilage defects. Overall, an efficient expansion of human macro-cartilage with superior regenerative plasticity is achieved, providing a promising strategy for joint regeneration.

Chondrocyte Isolation from Loose Bodies-An Option for Reducing Donor Site Morbidity for Autologous Chondrocyte Implantation

Loose bodies (LBs) from patients with osteochondritis dissecans (OCD) are usually removed and discarded during surgical treatment of the defect. In this study, we address the question of whether these LBs contain sufficient viable and functional chondrocytes that could serve as a source for autologous chondrocyte implantation (ACI) and how the required prolonged in vitro expansion affects their phenotype. Chondrocytes were isolated from LBs of 18 patients and compared with control chondrocyte from non-weight-bearing joint regions (n = 7) and bone marrow mesenchymal stromal cells (BMSCs, n = 6) obtained during primary arthroplasty. No significant differences in the initial cell yield per isolation and the expression of the chondrocyte progenitor cell markers CD44 + /CD146+ were found between chondrocyte populations from LBs (LB-CH) and control patients (Ctrl-CH). During long-term expansion, LB-CH exhibited comparable viability and proliferation rates to control cells and no ultimate cell cycle arrest was observed within 12 passages respectively 15.3 ± 1.1 mean cumulative populations doublings (CPD). The chondrogenic differentiation potential was comparable between LB-CH and Ctrl-CH, but both groups showed a significantly higher ability to form a hyaline cartilage matrix in vitro than BMSC. Our data suggest that LBs are a promising cell source for obtaining qualitatively and quantitatively suitable chondrocytes for therapeutic applications, thereby circumventing donor site morbidity as a consequence of the biopsies required for the current ACI procedure.

Osteoarthritis as an Umbrella Term for Different Subsets of Humans Undergoing Joint Degeneration: The Need to Address the Differences to Develop Effective Conservative Treatments and Prevention Strategies

Osteoarthritis (OA) of joints such as the knee and hip are very prevalent, and the number of individuals affected is expected to continue to rise. Currently, conservative treatments after OA diagnosis consist of a series of increasingly invasive interventions as the degeneration and pain increase, leading very often to joint replacement surgery. Most interventions are focused on alleviating pain, and there are no interventions currently available that stop and reverse OA-associated joint damage. For many decades OA was considered a disease of cartilage, but it is now considered a disease of the whole multi-tissue joint. As pain is the usual presenting symptom, for most patients, it is not known when the disease process was initiated and what the basis was for the initiation. The exception is post-traumatic OA which results from an overt injury to the joint that elevates the risk for OA development. This scenario leads to very long wait lists for joint replacement surgery in many jurisdictions. One aspect of why progress has been so slow in addressing the needs of patients is that OA has been used as an umbrella term that does not recognize that joint degeneration may arise from a variety of mechanistic causes that likely need separate analysis to identify interventions unique to each subtype (post-traumatic, metabolic, post-menopausal, growth and maturation associated). A second aspect of the slow pace of progress is that the bulk of research in the area is focused on post-traumatic OA (PTOA) in preclinical models that likely are not clearly relevant to human OA. That is, only ~12% of human OA is due to PTOA, but the bulk of studies investigate PTOA in rodents. Thus, much of the research community is failing the patient population affected by OA. A third aspect is that conservative treatment platforms are not specific to each OA subset, nor are they integrated into a coherent fashion for most patients. This review will discuss the literature relevant to the issues mentioned above and propose some of the directions that will be required going forward to enhance the impact of the research enterprise to affect patient outcomes.