Matrix induced autologous chondrocyte implantation in the knee: Comparison between osteochondritis dissecans and osteonecrosis and effect of chondrocyte thickness on prognosis.

OBJECTIVE The aim of this study was compare the clinical success of treatments for avascular necrosis and osteochondritis dissecans in cases who underwent matrix autologous chondrocyte implantations, and evaluate cartilage thickness on the clinical outcomes after implantation. METHODS A total of 37 patients (29 men, and 8 women; mean age: 23.8 years (16-38)) were treated prospectively with a two-stage matrix autologous chondrocyte implantation (avascular necrosis, n=21; osteochondritis dissecans, n=18). Clinical improvements and follows-up were assessed based on the patients' International Cartilage Repair Society (ICRS) scores with simultaneous cartilage thickness measurement using short-TI inversion recovery magnetic resonance imaging. The patients were divided into four subgroups based on their clinical scores, as group D <65 points, Group C 65-83 points, Group B 84-90 and Group A ≥90. RESULTS The mean ICRS score was 28.33±7.14 in the preoperative period in the avascular necrosis group, which increased to 70.88±12.61 at 60 months; while the mean ICRS score increased from 29.75±7.15 preoperatively to 87.58±12.83 at 60 months in the osteochondritis dissecans group. A statistically significant difference in the ICRS scores was noted between the two groups, and also between the ICRS scores and cartilage thicknesses of the subgroups (p<0.05). CONCLUSION Our study results revealed that greater clinical improvement was achieved in patients with osteochondritis dissecans undergoing matrix autologous chondrocyte implantation than in those with avascular necrosis. In addition, cartilage thickness greater than 3.7 mm following an autologous chondrocyte transplantation showed excellent clinical improvement. LEVEL OF EVIDENCE Level III, Therapeutic Study.