Surgical treatment of osteochondral lesions of the talus by open-field autologous chondrocyte implantation: a 10-year follow-up clinical and magnetic resonance imaging T2-mapping evaluation.

BACKGROUND: Ideal treatment of osteochondral lesions of the talus is still controversial. Although good clinical and histologic results have been reported for the knee, long-term results have not been reported for autologous chondrocyte implantation in the ankle. Furthermore, magnetic resonance imaging T2 mapping is becoming an increasingly used method for noninvasive assessment of repair tissue in the knee, but no experience on the ankle has been reported. HYPOTHESIS: The 10-year clinical results of autologous chondrocyte implantation in the treatment of osteochondral lesions of the talus has clinical efficacy comparable with the long-term efficacy of autologous chondrocyte implantation in the knee. A secondary hypothesis is that magnetic resonance imaging T2 mapping may provide noninvasive assessment of the repaired tissue quality in the ankle. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between 1997 and 1999, 10 patients (age 25.8 +/- 6.4 years) with an osteochondral lesion of the talus were treated with autologous chondrocyte implantation. The mean size of the lesions was 3.1 cm(2) (range, 2.2-4.3 cm(2)). All patients were evaluated clinically (American Orthopaedic Foot and Ankle Society score), radiographically, and by magnetic resonance imaging preoperatively and at established intervals up to a mean follow-up of 119 +/- 6.5 months. At the final follow-up, magnetic resonance imaging was graded with the Magnetic Resonance Observation of Cartilage Repair Tissue scoring system and T2-mapping evaluation in 6 cases. RESULTS: Before surgery, the mean American Orthopaedic Foot and Ankle Society score was 37.9 +/- 17.8 points, while at final follow-up it was 92.7 +/- 9.9 (P < .0005). Magnetic resonance imaging showed well-modeled restoration of the articular surface. The regenerated cartilage showed a mean T2-mapping value of 46 microseconds (range, 34-50), with no significant difference compared with that of healthy hyaline cartilage. CONCLUSION: The results of autologous chondrocyte implantation in the ankle joint are comparable with those in the knee as demonstrated by the significant clinical improvement, hyaline cartilage repair, and the durability of the results. Integration of both T2 mapping and Magnetic Resonance Observation of Cartilage Repair scoring permitted adequate evaluation of the repair site in the ankle.