Autologous minced cartilage repair for chondral and osteochondral lesions of the knee joint demonstrates good postoperative outcomes and low reoperation rates at minimum five-year follow-up

A light-cured injectable composite hydrogel based on chitosan and decellularized matrix modulates stem cell aggregation behavior for accelerating cartilage defect repair

Cartilage repair remains a formidable challenge because of its limited regenerative capacity. Construction of a biomimetic hydrogel matrix that can induce cell aggregation is a promising therapeutic option. Cell aggregates are more beneficial than dissociated cells for improving survival and chondrogenic differentiation, thereby facilitating cartilage repair. Herein, we report a light-cured injectable composite hydrogel with cellular aggregation properties for cartilage defect repair that combines methacrylated chitosan (CSMA) and a methacrylate-modified decellularized extracellular matrix (dECMMA). The CSMA promotes cell aggregate formation by enhancing cadherin expression. The dECMMA retains many inherent components and bioactive factors, thereby providing a more natural microenvironment for cell proliferation and differentiation. By precisely adjusting the compositions of the CSMA and dECMMA, it was possible to fine-tune their physicochemical properties and biochemical cues. The results showed that a composite hydrogel composed of 2 % (m/v) CSMA and 5 % (m/v) dECMMA exhibited good injectability, appropriate degradability and mechanical properties, and regulated the formation of bone marrow mesenchymal stem cell aggregates. Transplantation of the composite hydrogel loaded with bone marrow mesenchymal stem cells (BMSCs) into a cartilage defect model demonstrated effective hyaline cartilage repair. Thus, light-cured injectable composite hydrogels embedded with BMSCs holds clinical promise for cartilage defect repair.

Inconsistencies in clinically significant outcome metrics for knee cartilage repair: a systematic review

To systematically review the variability of reporting of clinically significant outcomes (CSOs) including minimal clinically important difference (MCID), substantial clinical benefit (SCB) and patient acceptable symptom state (PASS), and threshold calculation methods following surgical treatments for cartilage defects of the knee. A systematic review was performed using the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. A literature search was performed on August 12th, 2024, using the PubMed, Embase, and Scopus online databases for human clinical studies with publication dates ranging from 2010 to 2024 reporting on MCID, SCB, or PASS following surgical treatments for cartilage defects of the knee. Study demographics, patient-reported outcome measures (PROMs), CSO thresholds, and methods of CSO calculation were collected. A total of 19 studies (n = 3659 patients) with an average follow-up of 36.5 months were included. A total of 14 (93.3%) studies reported MCID, six (31.8%) studies reported SCB, and five (26.3%) studies reported PASS. Of the included studies, 16 (80%) referenced another study for calculating their CSO whereas three (20%) studies calculated their own CSO. A total of 16 different PROMs were reported among the included studies. Eight studies utilized the anchor-based method for CSO calculation, ten studies used both the anchor and the distribution-based methods for calculation, while only one study used the distribution-based method alone. There is considerable variation in the reporting and calculation methods of MCID, SCB, and PASS for different PROMs following surgical treatments for cartilage defects of the knee.Level of Evidence: IV, Systematic Review of Level I-IV studies.

Arthroscopic Minced Cartilage Implantation for Chondral Lesion at the Glenoid in the Shoulder: Technical Note

Joint cartilage damage is a common condition, and various approaches exist to address these defects. Whenever conservative treatments have been exhausted or are inadequate, surgery should be taken into consideration. However, it is essential to consider the size of the damage as well as the subchondral bone involvement. As joint replacement is not an appropriate treatment for young people, a joint-preserving technique should be preferred. One option is minced cartilage implantation. This surgical procedure is appropriate for defects of around 2 cm2. Studies demonstrated exceptional short-term and midterm outcomes in the knee and hip. This description of technique focuses on the implementation of AutoCart augmentation on the glenoid. The purpose of this note is to gain technical evidence of an all-arthroscopic cartilage implantation technique performed within the glenoid cavity.

Autologous minced cartilage implantation in osteochondral lesions of the talus-does fibrin make the difference?

INTRODUCTION

Implantation of minced cartilage is a one-step-procedure that leads to satisfactory results in osteochondral defects.

MATERIAL AND METHODS

A retrospective review was performed on a consecutive cohort of patients that received minced cartilage with fibrin (MCF), minced cartilage with membrane and fibrin (MCMF) and minced cartilage with the "AutoCart"-procedure (MCAC) between January 2019 and December 2023. Radiological outcome parameters were evaluated via Magnet-Resonance-Tomography (MRI) within one year using Ankle-Osteoarthritis-Scoring-System (AOSS).

RESULTS

Final data included 25 patients: 13 women and 12 men with a mean age of 28.2 years ± 10.9(range:18-51). Mean defect size was 103.6mm2 ± 59.0(95% CI = 79.2-128.0), mean depth 5.2 mm ± 3.6(3.7-6.6). Differences between groups in defect sizes were not significant (p = 0.999). MCF was carried out in 9(36.0%), MCMF in 7(28.0%) and MCAC in 9(36.0%) patients. Mean postoperative AOSS values were 2.6 ± 1.9(95%CI:1.1-4.1) for MCF-patients, 3.3 ± 2.9(0.6-5.9) for MCMF patients and 3.9 ± 2.8(1.7-6.1) for MCAC-patients, respectively. Differences were not significant (p = 0.639). Revision surgery because of symptomatic non-integration of the graft or ventral impingement occurred in 5(20%) of cases - all part of MCAC-patients that did not receive additional fibrin fixation as the top layer of transplant (p < 0.05).

CONCLUSIONS

Autologous minced cartilage implantation seems to be sufficient as a viable, one-step treatment for osteochondral lesions of the talus. It leads to low complication rates and excellent AOSS values within a 12-month period whereas the application of fibrin as the last fixation layer seems to be advisory, which demands further investigation.

High Rate of Return to Sport for Athletes Undergoing Articular Cartilage Restoration Procedures for the Knee: A Systematic Review of Contemporary Studies

BACKGROUND

Continued advancements in cartilage surgery and an accumulating body of evidence warrants a contemporary synthesis of return to sport (RTS) outcomes to provide updated prognostic data and to better understand treatment response.

PURPOSE

To perform an updated systematic review of RTS in athletes after knee cartilage restoration surgery.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

PubMed, OVID/Medline, and Cochrane databases were queried in October 2023 for studies reporting any RTS outcome after knee cartilage restoration surgery. Meta-analyses with inverse-variance proportion and DerSimonian-Laird random-effects estimators were applied to quantify overall RTS. Comparative proportional subgroup meta-analyses with relative odds ratios (ORs) were constructed to quantify (1) the influence of the procedure on RTS and (2) RTS ability (lower vs same/greater level of play) based on procedure, competition level, and specific sport.

RESULTS

A total of 52 studies (n = 2387) were included. The overall pooled RTS was 80.3% (95% CI, 73.3%-86.5%). Matrix-assisted chondrocyte implantation (MACI) (OR, 2.15) and osteochondral autograft transplantation system (OATS) (OR, 1.83) demonstrated the highest likelihoods of RTS at the same/greater level, while microfracture (MF) (OR, 0.78) was the only treatment demonstrating a higher likelihood of RTS at a lower level. The fastest mean RTS was observed after OATS (6.6 ± 2.6 months). Professional athletes demonstrated an OR of 1.01 for RTS at the same/greater level, whereas recreational/amateur athletes demonstrated an OR of 1.63; however, all professional athletes underwent MF, and recreational/amateur athletes who underwent MF demonstrated lower likelihoods of RTS (OR, 0.78), indicating a consistent association between MF and low RTS propensity. Basketball players demonstrated the lowest likelihood of RTS at the same/greater level (OR, 1.1), while American football and soccer were associated with high likelihoods of RTS (OR, 3 and 2.4, respectively) across all procedure types.

CONCLUSION

Cartilage restoration allows for high overall RTS, with OATS and MACI conferring the greatest propensity for RTS, while OATS allowed for the fastest RTS. Undergoing MF was associated with consistently poor RTS ability. This study identified several important associations between the level of RTS and clinically relevant factors when discussing RTS, with recreational/amateur athletes, soccer players, and American football players demonstrating a higher relative propensity to RTS.

One-stage minced cartilage autograft with platelet-rich plasma improves early clinical outcomes: A multicentric retrospective study

Purpose

Knee cartilage defects are a therapeutic challenge, often requiring multiple costly procedures with modest improvements. This study evaluates whether a one-stage minced cartilage autograft with platelet-rich plasma (PRP) improves clinical and radiological outcomes after at least 1 year.

Methods

A multicentric, non-randomized, retrospective analysis was conducted using data from two sports medicine centres. Sixty-six patients aged 18-50 years with symptomatic International Cartilage Repair Society Grade III/IV chondral defects underwent the minced cartilage autograft and PRP procedure between January 2021 and April 2023. The minimum follow-up was 1 year. Clinical scores for Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) Score and Self Knee Value (SKV) were collected from medical records and by an independent examiner at the latest follow-up. Magnetic resonance imaging (MRI) assessments using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 scoring system were performed at the latest follow-up in 46 patients (70%).

Results

The mean follow-up was 20.5 ± 7.5 months. The study demonstrated significant improvements in knee function and pain relief following the minced cartilage autograft with the PRP procedure. The mean KOOS total score started from 45.3 to 71.5 points, mean KOOS pain started from 51.9 to 80.4 points, mean KOOS activities of daily living started from 62.1 to 85.3 points, mean KOOS symptoms started from 53.1 to 79 points, mean KOOS sports started from 38.7 to 74.8 points, mean KOOS quality of life started from 43.3 to 73.7 points. The mean IKDC score improved by 27.7 ± 15.7 points. All these scores have been significantly improved (p < 0.05). MRI assessments confirmed the successful integration of repair tissue with a mean MOCART 2.0 score of 80.5 ± 12.5 points.

Conclusion

The minced autograft cartilage technique with PRP provides favourable early clinical and radiological outcomes for limited chondral defects in the knee. This method offers a single-procedure approach with minimal grafting requirements and does not necessitate a laboratory or specialized personnel, unlike other techniques.

Level of Evidence

Level III retrospective multicentric study.

Arthroscopic Autologous Minced Cartilage Implantation of Cartilage Defects in the Knee: A 2-Year Follow-up of 62 Patients

Background

Symptomatic cartilage defects of the knee joint are frequently diagnosed and can be treated with different available surgical methods. Nevertheless, there is currently no gold standard treatment for all indications. Minced cartilage implantation is increasingly coming into focus as a refined surgical technique.

Purpose

To investigate the 2-year clinical and radiological outcomes of arthroscopic autologous minced cartilage repair with the standardized commercial implantation system AutoCart.

Study Design

Case series; Level of evidence, 4.

Methods

A total of 62 consecutive patients were included and prospectively evaluated preoperatively and at 3, 6, 12, and 24 months postoperatively. Outcomes were assessed using the Knee injury and Osteoarthritis Outcome Score (KOOS), visual analog scale (VAS) for pain, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Single Assessment Numeric Evaluation (SANE), and Tegner activity scale at all follow-up time points. The examination of preoperative magnetic resonance imaging (MRI) was performed using the Area Measurement and Depth and Underlying Structures (AMADEUS) score, and the examination of MRI at 24 months was performed using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) 2.0 score.

Results

There were 34 male and 28 female patients (mean age, 38.79 ± 10.78 years) with symptomatic cartilage lesions with a mean defect size of 2.53 ± 1.24 cm2. Lesions were predominantly International Cartilage Repair Society grade 3 located in the region of the femoral condyles. Concomitant surgery was performed in 40.3% of patients. The total KOOS score significantly improved from 62.4 ± 13.1 at baseline to 74.4 ± 15.9 at 24 months (P < .001). The secondary outcome measures of the VAS, WOMAC, and SANE showed a similar pattern, with score improvements in the follow-up period compared to baseline. The mean AMADEUS score was 64.75 ± 13.87, while the mean MOCART 2.0 score was 62.88 ± 9.86, among 20 available patients. The revision surgery rate was 8.1% mainly because of hypertrophy (6.5%).

Conclusion

Among this cohort of patients, minced cartilage implantation demonstrated satisfying 2-year outcomes with increased patient-reported outcome measure scores from 3 to 24 months postoperatively. Regenerated tissue quality on MRI was comparable to that using other cartilage repair methods and showed no associations with patient characteristics or patient-reported outcome measures. Larger cohorts, longer postoperative intervals, and comparable trials are needed to further evaluate the role of this technique in treating cartilage defects.

Autologous matrix-induced chondrogenesis provides better outcomes in comparison to autologous minced cartilage implantation in the repair of knee chondral defects

PURPOSE

In symptomatic mid-sized focal chondral defects, autologous matrix-induced chondrogenesis (AMIC) and minced cartilage implantation (MCI) offer two versatile treatment options. This study aimed to conduct a matched-patient analysis of patient-reported outcome measures to compare these two surgical treatment methods for focal chondral defects.

METHODS

At the first centre, patients underwent a single-stage procedure in which autologous cartilage was hand-minced, implanted into the defect and fixed with fibrin glue. At the second centre, patients underwent AMIC, which was fixed in place with fibrin glue. All patients were seen 2-4 years postoperatively. Postoperative outcomes were assessed using the visual analogue scale for pain (VAS), the Lysholm score and the five domains of the knee osteoarthritis outcome score (KOOS). Patients from each surgical centre were matched by age, sex, defect size and defect localisation.

RESULTS

In total, 48 patients from two surgical centres (24 from each site) were matched for sex, age (MCI 30.3 ± 14.9 years vs. AMIC 30.8 ± 13.7 years) and defect size (MCI 2.49 ± 1.5 cm2 vs. AMIC 2.65 ± 1.1 cm2). Significantly better scores in the AMIC cohort were noted for VAS (p = 0.004), Lysholm (p = 0.043) and the KOOS subscales for pain (p = 0.016) and quality of life (p = 0.036). There was a significantly greater proportion of positive responders for Lysholm in the AMIC group (92%) compared with the MCI group (64%).

CONCLUSIONS

The AMIC procedure delivers superior patient outcomes compared with hand-minced autologous cartilage implantation. These are mid-term outcomes, with follow-up between 2 and 4 years.

LEVEL OF EVIDENCE

Level III.

Autologous platelet-rich plasma and fibrin-augmented minced cartilage implantation in chondral lesions of the knee leads to good clinical and radiological outcomes after more than 12 months: A retrospective cohort study of 71 patients

Purpose

The treatment of cartilage lesions remains a challenge. Matrix-associated autologous chondrocyte implantation has evolved to become the gold standard procedure. However, this two-step procedure has crucial disadvantages, and the one-step minced cartilage procedure has gained attention. This retrospective study aimed to evaluate the clinical and radiological outcome of an all-autologous minced cartilage technique in cartilage lesions at the knee joint.

Methods

In this retrospective cohort study, 71 patients (38.6 years ± 12.0, 39,4% female) with a magnetic resonance imaging (MRI) confirmed grade III-IV cartilage defect at the medial femur condyle (n = 20), lateral femur condyle (n = 2), lateral tibia plateau (n = 1), retropatellar (n = 28) and at the trochlea (n = 20) were included. All patients were treated with an all-autologous minced cartilage procedure (AutoCart™). Clinical knee function was evaluated by the Tegner score, visual analogue scale, the subjective and objective evaluation form of the International Knee Documentation Committee and the Knee Injury and Osteoarthritis Outcome Score (KOOS). MRI analyses were performed by magnetic resonance observation of cartilage repair tissue (MOCART) 2.0 knee score. Follow-up examination was 13.7 ± 4.2 (12-24) months postoperative.

Results

All clinical scores significantly improved after surgical intervention (p < 0.0001), especially the subgroup sports and recreation of KOOS showed clear changes from baseline in the follow-up examination. In the postoperative MRI evaluation, 39 of 71 patients showed a complete fill of the cartilage defect without subchondral changes in 78% of the patients in the MOCART 2.0 score in the follow-up analysis. None of the patients showed adverse effects, which are linked to the minced cartilage procedure during the time of follow-up.

Conclusion

An all-autologous minced cartilage technique for chondral lesions at the knee joint seems to be an effective and safe treatment method with good clinical and radiological short-term results.

Level of Evidence

Level IV.

Evaluation of Tibiofemoral Contact Mechanics After a Novel Hybrid Procedure for Femoral Osteochondral Defect Repairs With a Subchondral Implant and Dermal Matrix

Background

There is a lack of procedures that adequately address the subchondral bone structure and function for reconstructing osteochondral defects in the femoral condyles.

Purpose

To biomechanically evaluate the tibiofemoral joint contact characteristics before and after reconstruction of femoral condylar osteochondral defects using a novel hybrid reconstructive procedure, which was hypothesized to restore the contact characteristics to the intact condition.

Study Design

Controlled laboratory study.

Methods

Tibiofemoral contact areas, contact forces, and mean contact pressures were measured in 8 cadaveric knees (mean age 52 ± 11 years; 6 women, 2 men) using a custom testing system and pressure mapping sensors. Five conditions were tested for each condyle: intact, 8-mm defect, 8-mm repair, 10-mm defect, and 10-mm repair. Medial femoral condylar defects were evaluated at 30° of knee flexion and lateral condylar defects were evaluated at 60° of knee flexion, with compressive loads of 50, 100, and 150 N. The defects were reconstructed with a titanium fenestrated threaded implant countersunk in the subchondral bone and an acellular dermal matrix allograft. Repeated-measures analysis of variance with Bonferroni correction for multiple comparisons was used to compare the results between the 5 testing conditions at each load.

Results

Medial condylar defects significantly increased mean contact pressure on the lateral side (P < .042), which was restored to the intact levels with repair. The lateral condylar defect decreased the mean contact pressure laterally while increasing the mean pressure medially. The lateral and medial mean contact pressures were restored to intact levels with the 8-mm lateral condylar defect repair. The medial mean contact pressure was restored to intact levels with the 10-mm lateral condylar defect repair. The lateral mean contact pressure decreased compared with the intact state with the lateral condylar 10-mm defect repair.

Conclusion

Tibiofemoral joint contact pressure was restored to the intact condition after reconstruction of osteochondral defects with dermal allograft matrix and subchondral implants for the repair of both 8- and 10-mm lateral condylar defects as well as 8-mm medial condylar defects but not completely for 10-mm medial condylar defects.

Clinical Relevance

The novel hybrid procedure for osteochondral defect repair restored tibiofemoral joint contact characteristics to normal in a cadaveric model.

Factors Affecting Choice of Surgical Treatment of Cartilage Lesions of the Knee: An Analysis of Data From 5143 Patients From the German Cartilage Registry (KnorpelRegister DGOU)

Background

Symptomatic full-thickness cartilage lesions of the knee joint are considered an indication for cartilage repair surgery. Patient- and lesion-specific factors like age, nutritional status, etiology of defect, or integrity of corresponding joint surface remain controversial in indicating cartilage repair surgery. Furthermore, the selection of the most suitable cartilage repair technique for a specific cartilage lesion remains debatable.

Purpose

To evaluate indications and choice of treatment method for cartilage repair surgery, depending on patient- and lesion-specific data from the German Cartilage Registry.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A total of 6305 consecutive patients who underwent cartilage repair surgery of the knee evaluated and 5143 complete datasets were included in the analysis (follow-up rate, 81.5%). Patient-specific (age, body mass index, smoking status, previous operations, clinical leg axis) and lesion-specific (size, grading, location, etiology) data were provided by the attending surgeon at the time of surgery. Appropriate statistical tests were used to compare data depending on type and normality of data. Multivariable logistic regressions were calculated to investigate independent factors for the choice of specific cartilage repair techniques.

Results

The median size of treated cartilage lesions was 3.6 cm2, and most defects were of degenerative origin (54.8%). Of the registered patients, 39.2% were categorized as overweight and 19.6% as obese, while 23.3% were smokers. The most prevalently documented operative techniques were the autologous chondrocyte implantation (ACI) (52.4%), bone marrow stimulation (BMS) (17.3%), and BMS augmented with collagen scaffolds (9.3%). Independent factors that made the use of ACI more likely were bigger lesion size, previous surgery at the joint, and lesions located at the trochlea or the patella. On the contrary, BMS or augmented BMS were preferred in older patients, with damaged corresponding joint surface, and with more concomitant surgeries.

Conclusion

Cartilage repair surgery was indicated irrespective of nutritional status, smoking status, or etiology of the treated lesion. ACI was the most prevalent technique and was preferred for younger patients and patellar lesions. While older patients with degenerative changes to the joint were not excluded from cartilage repair surgery, the use of ACI was restricted.

Bioprinted biomimetic hydrogel matrices guiding stem cell aggregates for enhanced chondrogenesis and cartilage regeneration

Articular cartilage tissue has limited self-repair capabilities, with damage frequently progressing to irreversible degeneration. Engineered tissues constructed through bioprinting and embedded with stem cell aggregates offer promising therapeutic alternatives. Aggregates of bone marrow mesenchymal stromal cells (BMSCs) demonstrate enhanced and more rapid chondrogenic differentiation than isolated cells, thus facilitating cartilage repair. However, it remains a key challenge to precisely control biochemical microenvironments to regulate cellular adhesion and cohesion within bioprinted matrices simultaneously. Herein, this work reports a bioprintable hydrogel matrix with high cellular adhesion and aggregation properties for cartilage repair. The hydrogel comprises an enhanced cell-adhesive gelatin methacrylate and a cell-cohesive chitosan methacrylate (CHMA), both of which are subjected to photo-initiated crosslinking. By precisely adjusting the CHMA content, the mechanical stability and biochemical cues of the hydrogels are finely tuned to promote cellular aggregation, chondrogenic differentiation and cartilage repair implantation. Multi-layer constructs encapsulated with BMSCs, with high cell viability reaching 91.1%, are bioprinted and photo-crosslinked to support chondrogenic differentiation for 21 days. BMSCs rapidly form aggregates and display efficient chondrogenic differentiation both on the hydrogels and within bioprinted constructs, as evidenced by the upregulated expression of Sox9, Aggrecan and Collagen 2a1 genes, along with high protein levels. Transplantation of these BMSC-laden bioprinted hydrogels into cartilaginous defects demonstrates effective hyaline cartilage repair. Overall, this cell-responsive hydrogel scaffold holds immense promise for applications in cartilage tissue engineering.

Collagen 1 gel may improve the regenerative capacity of minced adult and preosteoarthritic cartilage

PURPOSE

Minced cartilage implantation (MCI) is an evolving technique for the treatment of osteochondral lesions. It was hypothesised that mincing of cartilage may affect chondrocyte viability and phenotype and that embedding in collagen 1 gel results in an improved outcome. The objective of this study was to evaluate the impact of cartilage mincing and whether collagen 1 gel mediates beneficial effects on the chondrocyte phenotype and viability.

METHODS

Human cartilage samples from 11 patients undergoing total knee arthroplasty were collected and minced according to the MCI protocol. Minced cartilage was cultured for 1 week with and without embedding in collagen 1 gel and was compared with unminced cartilage flakes as control. Quantitative reverse transcription-PCR and immunohistochemical staining for the chondrocyte marker genes SOX9, COL2, ACAN, COL10 and MMP13 were used to examine the chondrocyte phenotype. Cell death was assessed by the terminal deoxynucleotidyl transferase dUTP nick-end labeling assay.

RESULTS

Increased chondrocyte cell death of cultured cartilage after mincing was observed. Chondrocytes from minced cartilage exhibited significantly decreased expression and protein levels of homeostatic and hypertrophic chondrocyte markers. Embedding in collagen 1 gel showed no positive effect on viability. However, remarkable is the increased expression of ACAN and the preserved protein level of SOX9 in the collagen 1-embedded minced cartilage.

CONCLUSIONS

This study shows that the mincing of cartilage leads to increased chondrocyte death and decreased expression of chondrocyte phenotypic marker genes after 7 days. The use of collagen 1 gel may improve the stability of the phenotype, which needs to be further elucidated.

LEVEL OF EVIDENCE

Level III (therapeutic).