Long-term Results of Autologous Chondrocyte Implantation in the Knee for Chronic Chondral and Osteochondral Defects

Background: Autologous chondrocyte implantation (ACI) has been shown to be effective in the midterm for the treatment of symptomatic articular cartilage lesions of the knee, but few long-term series have been published. The multioperated chronic articular cartilage defect remains a difficult condition to treat. Purpose: To examine the long-term clinical results of ACI for large chronic articular cartilage defects, many treated as salvage. Study Design: Case series; Level of evidence, 4. Methods: This is a prospective case series of 104 patients with a mean age of 30.2 years and a symptomatic lesion of the articular cartilage in the knee, who underwent ACI between 1998 and 2001. The mean duration of symptoms before surgery was 7.8 years. The mean number of previous surgical procedures on the cartilage defect, excluding arthroscopic debridement, was 1.3. The defects were large, with a mean size of 477.1 mm(2) (range, 120-2500 mm(2)). The modified Cincinnati, Stanmore/Bentley, and visual analog scale for pain scoring systems were used to assess pain and functional outcomes at a minimum 10 years (mean, 10.4 years; range, 10-12 years). Results: Twenty-seven patients (26%) experienced graft failure at a mean of 5.7 years after ACI. Of the 73 patients who did not fail, 46 patients (63% of patients with a surviving graft) had an excellent result, 18 (25%) were good, 6 (8%) were fair, and 3 (4%) had a poor result. Of a total of 100 patients successfully followed up, 98 were satisfied with the ACI technique for their chronic knee pain and would undergo the procedure again. Conclusion: Autologous chondrocyte implantation can provide a long-term solution in more than 70% of young patients of a difficult-to-treat group with large chronic articular cartilage lesions, even in the salvage situation.