Good clinical results with autologous matrix-induced chondrogenesis (Amic) technique in large knee chondral defects

Abstract

Purpose: Autologous matrix-induced chondrogenesis (AMIC) is a treatment for focal full-thickness cartilage defects combining microfracturing with an exogenous I/III collagen matrix (Chondro-Gide). The aim of the present study was to determine the 7 years outcomes of patients treated with the AMIC technique for knee chondral defects larger than 2 cm². The hypothesis was that the positive short-term outcomes achieved in the previous series would not deteriorate at a 7-year follow-up.

Methods: Twenty-one patients treated with the AMIC technique were retrospectively analysed. Patients were assessed through the IKDC subjective knee evaluation questionnaire and the Lysholm scoring system. All patients underwent a complete imaging study including radiographs and magnetic resonance. The median defect size was found to be 4.3 (range 2.9-8) cm².

Results: At a median follow-up of 7 (±1.4) years, the mean IKDC score improved from 31.7 (±8.9) points preoperatively, to 80.6 (±5.3) at the latest follow-up (p < 0.05). The mean Lysholm score improved from 38.8 (±12.4) points preoperatively to 72.6 (±19.5) points at the last follow-up (p < 0.05). At the last follow-up, 76.2% of patients were satisfied or extremely satisfied with their outcomes, while 66.6% of patients showed good quality repair tissue on magnetic resonance imaging.

Conclusion: AMIC was found to be an effective method to treat full-thickness knee chondral defects larger than 2 cm², with significant clinical and functional improvement maintained over a 7-year follow-up.

Level of evidence: IV.

Keywords: AMIC; Chondro-Gide; Chondrogenesis; Knee chondral defects; Microfracturing.