The Predictive Value of Early Postoperative MRI-Based Bone Marrow Parameters for Mid-Term Outcome after MACI with Autologous Bone Grafting at the Knee

The role of autologous bone grafting in matrix-associated autologous chondrocyte implantation at the knee: Results from the German Cartilage Registry (KnorpelRegister DGOU)

PURPOSE

To investigate whether concomitant autologous bone grafting adversely affects clinical outcome and graft survival after matrix-associated autologous chondrocyte implantation (M-ACI).

METHODS

The present study examines registry data of patients who underwent M-ACI with or without autologous bone grafting for large-sized chondral or osteochondral defects. Propensity score matching was performed to exclude potential confounders. A total of 215 patients with similar baseline characteristics were identified. Clinical outcome was assessed at the time of surgery and at 6, 12, 24, 36 and 60 months using the Knee Injury and Osteoarthritis Outcome Score (KOOS). KOOS change, clinical response rate, KOOS subcomponents and failure rate were determined.

RESULTS

Patients treated with M-ACI and autologous bone grafting achieved comparable clinical outcomes compared with M-ACI alone. At 24 months postoperatively, the patient-reported outcome (PRO) of patients treated with M-ACI and autologous bone grafting was even significantly better as measured by KOOS (74.9 ± 18.8 vs. 79.2 ± 15.4; p = 0.043). However, the difference did not exceed the minimal clinically important difference (MCID). In patients with M-ACI and autologous bone grafting, a greater change in KOOS relative to baseline was observed at 6 (9.3 ± 14.7 vs. 15.0 ± 14.7; p = 0.004) and 12 months (12.6 ± 17.2 vs. 17.7 ± 14.6; p = 0.035). Overall, a high clinical response rate was observed in both groups at 24 months (75.8% vs. 82.0%; p = n.s.). The estimated survival at the endpoint of reoperation for any reason was 82.1% (SD 2.8) at 8.4 years for isolated M-ACI and 88.7% (SD 2.4) at 8.2 years for M-ACI with autologous bone grafting (p = 0.039).

CONCLUSIONS

Even in the challenging cohort of large osteochondral defects, the additional treatment with autologous bone grafting leads to remarkably good clinical outcomes in patients treated with M-ACI. In fact, they tend to benefit more from surgery, have lower revision rates and achieve clinical response rates earlier. Subchondral bone management is critical to the success of M-ACI and should be addressed in the treatment of borderline defects.

LEVEL OF EVIDENCE

Level III.

Knee Joint Preservation in Tactical Athletes: A Comprehensive Approach Based upon Lesion Location and Restoration of the Osteochondral Unit

The unique physical demands of tactical athletes put immense stress on the knee joint, making these individuals susceptible to injury. In order to ensure operational readiness, management options must restore and preserve the native architecture and minimize downtime, while optimizing functionality. Osteochondral lesions (OCL) of the knee have long been acknowledged as significant sources of knee pain and functional deficits. The management of OCL is predicated on certain injury characteristics, including lesion location and the extent of subchondral disease. Techniques such as marrow stimulation, allograft and autologous chondrocyte implantation are examined in detail, with a focus on their application and suitability in tactical athlete populations. Moreover, the restoration of the osteochondral unit (OCU) is highlighted as a central aspect of knee joint preservation. The discussion encompasses the biomechanical considerations and outcomes associated with various cartilage restoration techniques. Factors influencing procedure selection, including lesion size, location, and patient-specific variables, are thoroughly examined. Additionally, the review underscores the critical role of post-operative rehabilitation and conditioning programs in optimizing outcomes. Strengthening the surrounding musculature, enhancing joint stability, and refining movement patterns are paramount in facilitating the successful integration of preservation procedures. This narrative review aims to provide a comprehensive resource for surgeons, engineers, and sports medicine practitioners engaged in the care of tactical athletes and the field of cartilage restoration. The integration of advanced preservation techniques and tailored rehabilitation protocols offers a promising avenue for sustaining knee joint health and function in this demanding population.

Satisfactory patient-reported outcomes in patients treated with impaction bone grafting and autologous matrix-induced chondrogenesis for osteochondral knee defects

PURPOSE

Osteochondral knee defects usually affect young, active patients and may alter knee biomechanics and progressively lead to joint degeneration. Various treatment options exist with autologous, impaction bone grafting in combination with autologous matrix-induced chondrogenesis (BG-AMIC) being a less-expensive, one-step, promising option. The purpose of this study is to evaluate the clinical and radiological mid-term outcomes of large osteochondral lesions treated with BG-AMIC, identify a possible correlation between the two and report postoperative complications and reoperation rate.

METHODS

A retrospective analysis of 25 patients treated with the BG-AMIC technique for knee osteochondral lesions was performed. Patients were assessed using the following PROMs: the IKDC, the KOOS and the Lysholm score, the Tegner activity scale and a patient acceptable symptom state (PASS). The EQ-5D-5L score was used to assess health-related quality of life. Radiological assessment was performed using the MOCART 2.0 score on a 3 T MRI.

RESULTS

At a mean of 3.8 (± 0.8)-year follow-up, all functional scores increased significantly (p < 0.005) when compared to the preoperative baseline. IKDC increased from 44.5 (± 15.9) to 81.4 (± 14.7), KOOS from 41.5 (± 16.1) to 91.6 (± 11.6) and Lysholm from 54.4 (± 23) to 95.2 (± 5.5) (p < 0.005). The EQ-5D-5L score also revealed a significant improvement [59.9 (± 25) to 93.4 (± 10.2), p < 0.005]. Mean Tegner score reached pre-injury levels. The PASS was positive in 100% of patients. The minimum clinically important difference was reached in all PROMs except for the KOOS Sports subscale. There were no re-operations. Morphological evaluation of the repair tissue using the MOCART 2.0 score revealed a mean total score of 52.8 (± 30.5). A statistically significant, positive correlation was found between the MOCART 2.0 score and the IKDC score, the KOOS ADL subscale and the EQ-5D-5L (p < 0.05).

CONCLUSION

BG-AMIC is a safe and reliable option for treating deep, knee osteochondral lesions, providing a statistically significant and clinically important improvement in patient-reported outcomes. No complications were noticed, and no re-operations were performed after the procedure. A moderate positive correlation between the MOCART 2.0 score and the IKDC, KOOS ADL and EQ-5D-5L was noticed. However, this correlation is not necessarily clinically relevant, and excellent clinical results can be expected even in patients with low MOCART scores.

LEVEL OF EVIDENCE

III.

The AMADEUS score is not a sufficient predictor for functional outcome after autologous chondrocyte implantation (ACI) of the knee: data from the German Cartilage Registry (KnorpelRegister DGOU)

INTRODUCTION

The AMADEUS (Area Measurement And DEpth and Underlying Structures) score has advanced to a commonly used tool for MRI-based chondral defect severity grading prior to cartilage knee surgery. It was the intention of this study to assess the AMADEUS for a potential correlation with clinical data by patient-reported outcome measures (PROMs).

METHODS

A total of 51 patients undergoing ACI (autologous chondrocyte implantation) between 2016 and 2022 were found eligible and retrospectively analyzed. All patients were registered in the German Cartilage Registry prior to surgery and follow-up data were collected using the Knee Osteoarthritis Outcome score (KOOS), the International Knee Documentation Committee (IKDC) Form and the numeric rating scale (NRS). Pre-operative MRI images were scored by three raters using the AMADEUS classification system, and an overall AMADEUS score was calculated which was subsequently correlated with pre- and post-operative PROMs.

RESULTS

Mean patient age was 32.67 ± 8.37 years and mean defect size area 343.04 mm2 ± 139.45 mm2. No correlative capacity of the pre- and postoperative IKDC, KOOS or NRS scores was found with the AMADEUS final score or any of its subscores. From the pre- to postoperative visit, a significant improvement of the PROMs (IKDC: 45.53 ± 21.00 vs. 59.83 ± 17.93, p = 0.04; KOOS Pain: 58.00 ± 16.70 vs. 76.06 ± 19.20, p = 0.03; KOOS ADL: 64.17 ± 18.76 vs. 82.11 ± 16.68, p < 0.01; KOOS Sports: 26.11 ± 18.52 vs. 50.56 ± 23.94, p = 0.01; KOOS QOL: 25.50 ± 14.26 ± 45.28 ± 19.03, p = 0.00) was found. Intraclass correlation coefficients showed an overall good interrater agreement for the AMADEUS total score (ICC = 0.75).

CONCLUSIONS

Study results suggest no correlative capacity of the AMADEUS with routinely used PROMs in patients undergoing ACI. Therefore, radiographically assessed cartilage defect characteristics poorly translate to pre- and postoperative patient-reported outcome data.

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

PURPOSE

To evaluate the safety and efficacy of matrix-associated autologous chondrocyte implantation (ACI) using spheroids in comparison to arthroscopic microfracture for the treatment of symptomatic cartilage defects of the knee.

METHODS

In a prospective multicenter-controlled trial, patients aged between 18 and 50 years, with single symptomatic focal cartilage defects between 1 and 4 cm² (mean 2.6 ± 0.8, median 2.75, range 1.44-5.00) in the knee were randomized to treatment with ACI with spheroids (n = 52) or microfracture (n = 50). Primary clinical outcome was assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS). Analyses were performed in a defined hierarchical manner where outcomes of ACI were first compared to baseline values followed by a comparison to the microfracture group with repeated-measures ANCOVA with a non-inferiority approach. Subgroup analyses were performed to investigate the influence of age and defect size on the overall KOOS. Secondary clinical outcomes were the magnetic resonance observation of cartilage repair tissue (MOCART), modified Lysholm score and International Knee Documentation Committee (IKDC) examination form. Safety data focused on adverse events. Here the 5 years results are presented at which there were 33 observed cases in the ACI group and 30 in the microfracture group.

RESULTS

The overall KOOS and its five subscores were significantly improved compared to baseline for both the ACI and microfracture group. Non-inferiority of ACI to microfracture was confirmed for the overall KOOS and the subscores, while for the subscores activities of daily living, quality of life and sports and recreation of the threshold for superiority was passed. In the ACI group, a notably more rapid initial improvement of the KOOS was found at three months for the older age group compared to the younger age group and the microfracture group. No other differences were found based on age or defect size. In addition, clinical improvement was found for the MOCART, modified Lysholm and IKDC examination form both the ACI and microfracture group. No safety concern related to either treatment was observed.

CONCLUSION

This study confirms the safety and efficacy of matrix-associated ACI with spheroids at a mid to long-term follow-up. Non-inferiority of ACI to microfracture was confirmed for the overall KOOS and all subscores, while superiority was reached for the subscores activities of daily living, quality of life and sports and recreation in the ACI group. This underlines the importance of ACI for the young and active patients.

LEVEL OF EVIDENCE

I.