Midterm Clinical and Radiological Outcome After Autologous Matrix-induced Chondrogenesis (AMIC) for Osteochondral Lesions of the Talus

Abstract

Introduction: Autologous matrix-induced chondrogenesis (AMIC) has recently become an interesting treatment option for osteochondral lesions of the talus since it combines safety and efficacy with overcoming several drawbacks of other surgical techniques. With AMIC, donor side morbidity of osteochondral autografts is eliminated, two-step procedures like matrix-induced autologous chondrocyte implantation are minimized to a more cost-effective single step and restrictions due to limited availability of osteochondral allografts are resolved. The purpose of this study was to evaluate the therapeutic efficacy of AMIC by analyzing AMIC-repaired osteochondral talar lesions in consecutively treated patients after a minimum follow-up of 2 years. Method(s): All patients with an osteochondral lesion of the talus treated with the AMIC technique completing a minimum follow-up of 2 years were enrolled in the study. 36 of the 47 eligible patients (58% males; mean age at surgery 34.8 (range, 13-75) years); body mass index 27.6 +/- 6.9 kg/m$sup$2$/sup$) were available for clinical (visual analogue scale (VAS), American Orthopaedic Foot and Ankle Society (AOFAS) score, Tegner Score) and radiological (Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system) evaluation. Result(s): After a mean follow-up of 4.5 (range, 2.3-7.9) years, the VAS improved signifcantly from 6.3 +/- 2.0 preoperatively to 1. 5 +/- 2.2 at follow-up (p <0.001). The mean AOFAS score was 92.9 8.1 (range, 74-100) points. The sports activity level improved signifcantly from 3.7 +/- 2.0 points preoperatively to 5.1 +/- 1. 8 points at follow-up (p <0.001); 17% did not reach their pre-injury level of activity due to persistent ankle pain. The MOCART score averaged 61.3 +/- 21.4 (range, 0-100) points. A complete flling of the defect was seen in 42%, of which 44% showed hypertrophy of the cartilage layer. Normal or nearly normal signal intensity was detected in 72%. All patients had subchondral bone edema or cysts. The MRI findings did not correlate with the clinical outcome. 92% were satisfed with the outcome and would undergo the same procedure again. Conclusion(s): AMIC is a reliable procedure to treat osteochondral lesions of the talus. Signifcant pain reduction and high ankle function were observed after a mean midterm follow-up of 4.5 years. MRI findings did not refect the good clinical results and therefore should be interpreted cautiously in patients with persistent symptoms.