Autologous Matrix-Induced Chondrogenesis for Osteochondral Lesions of the Talus: A Clinical and Radiological 2- to 8-Year Follow-up Study.

BACKGROUND: Autologous matrix-induced chondrogenesis (AMIC) has become an interesting treatment option for osteochondral lesions of the talus (OLTs) with promising clinical short- to midterm results.

PURPOSE: To investigate the clinical and radiological outcome of the AMIC procedure for OLTs, extending the follow-up to 8 years.

STUDY DESIGN: Case series; Level of evidence, 4.

METHODS: Thirty-three patients (mean age, 35.1 years; body mass index, 26.8) with osteochondral lesions of the medial talar dome were retrospectively evaluated after open AMIC repair at a mean follow-up of 4.7 years (range, 2.3-8.0 years). Patients requiring additional surgical procedures were excluded. All OLTs (mean size, 0.9 cm2 ; range, 0.4-2.3 cm2 ) were approached through a medial malleolar osteotomy, and 28 patients received subchondral autologous bone grafting. Data analysis included the visual analog scale for pain, the American Orthopaedic Foot and Ankle Society score for ankle function, the Tegner score for sports activity, and the MOCART (magnetic resonance observation of cartilage repair tissue) scoring system for repair cartilage and subchondral bone evaluation.

RESULTS: Mean ± SD visual analog scale score improved significantly from 6.4 ± 1.9 preoperatively to 1.4 ± 2.0 at latest follow-up ( P < .001). The mean American Orthopaedic Foot and Ankle Society score was 93.0 ± 7.5 (range, 75-100). The Tegner score improved significantly from 3.5 ± 1.8 preoperatively to 5.2 ± 1.7 at latest follow-up ( P < .001), and 79% returned to their previous sports levels. The MOCART score averaged 60.6 ± 21.2 (range, 0-100). Complete filling of the defect was seen in 88% of cases, but 52% showed hypertrophy of the cartilage layer. All but 1 patient showed persistent subchondral bone edema. The patient's age and body mass index, the size of the osteochondral lesion, and the MOCART score did not show significant correlation with the clinical outcome. There were no cases of revision surgery for failed AMIC. Fifty-eight percent underwent reoperation, mainly for symptomatic hardware after malleolar osteotomy.

CONCLUSION: AMIC for osteochondral talar lesions led to significant pain reduction, recovery of ankle function, and successful return to sport. The MOCART score did not correlate with the good clinical results; the interpretation of postoperative imaging remains therefore challenging.