What factors influence the results of ACT when the indication limits are exceeded?

Aim: The present study evaluates the results of ACT at the knee joint with transgression of the usual spectrum of indications and points out the possible limits of the method. Methods: In 20 of a total of 71 patients the indication limits of ACT were exceeded. The clinical follow-up over two years was related to the localisation, size, adjacent cartilage, previous and additional operations and the quality of the transplanted chondrocytes. Results: The average patient age at time of operation was 41.1 years (24 to 55 years). The average defect size was 7.9 cm(2) (3.75 to 14 cm(2)). In the analysed group outside of the indication limits of ACT half of the patients showed good or excellent results at clinical follow-up after 2 years. 10 patients. however. assessed the clinical situation as fair or poor. Within this group 5 patients showed a minimum of two lesions. In 6 patients the treated defect was not completely surrounded by an adjacent cartilage shoulder. In 7 cases the meniscus at the site of the lesion had been partially removed in a previous operation and osteoarthrosis or kissing lesions were detected in 4 cases. The persistent good cell quality had no negative influence on the postoperative results. Conclusion: The results after ACT are influenced by the adjacent cartilage shoulder, kissing lesions, previous meniscectomy and osteoarthrosis. This may limit the indications of the method.