Does AMIC® provide improvements at least two years after surgery for knee osteochondral lesions? A multicentre retrospective study of 101 patients.

BACKGROUND

Osteochondral defects of the knee due to trauma or osteochondritis are associated with osteoarthritis in the medium term. Defects 2 to 8cm2 in size can be managed by autologous matrix-induced chondrogenesis (AMIC®), in which sub-chondral micro-fractures are created within the lesion and the defect is then covered by a matrix of type I and type III collagen to induce de novo cartilage formation. Although promising outcomes have been observed in small single-centre cohorts, the medium-term clinical and radiological effectiveness of AMIC® remains to be demonstrated in larger populations. The objective of this study was to evaluate outcomes of patients at least 2 years after AMIC® for knee osteochondral defects.

HYPOTHESIS: AMIC® is associated with clinical and radiological improvements after at least 2 years.

MATERIAL AND METHOD: This multicentre (16 centres), multisurgeon (18 senior orthopaedic surgeons), retrospective study included consecutive patients who underwent AMIC® with Chondro-Gide® membrane implantation between September 2011 and January 2020. The 36-item Short Form quality-of-life (SF-36) score, Knee Injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) score were determined before the procedure and during follow-up. The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was assessed by magnetic resonance imaging 2 years after the procedure.

RESULTS

In total, 101 patients aged 12 to 60 years were included. Mean follow-up was 30 months. Mean defect size was 3.44cm2 (range, 2-8cm2). Significant improvements were documented in the SF-36 score, KOOS, and IKDC score. The mean MOCART score at 2 years was 75% (range, 20-100).

DISCUSSION: The AMIC® procedure was associated with significant improvements at 2.5 years in patients treated for knee osteochondral defects measuring 2 to 8cm2. This method seems to provide similar outcomes to those of other available methods with the advantages of single-step surgery and elimination of osteochondral graft donor-site complications.

LEVEL OF EVIDENCE: IV, retrospective observational cohort study.