A Randomized Controlled Trial Comparing "Early" Versus "Late" Periosteal Patch Attachment to Knee Chondral Defects in Autologous Chondrocyte Implantation.

Objective: Traditional autologous chondrocyte implantation (ACI) involves arthroscopically harvesting a cartilage biopsy (stage 1), followed by arthrotomy 3 to 4 weeks later to apply a periosteal patch and implant culture-expanded chondrocytes underneath (stage 2). This study aimed to determine if patch application during stage 1 rather than stage 2 improved clinical outcome.

Design: A randomized controlled trial was conducted from 1998 to 2001. Patients were randomized to receive either traditional ACI (control/late) or ACI with "early" patch during stage 1 (intervention/early). Clinical outcome (Lysholm score) was assessed pre-operatively and annually post-operatively.

Results: Seventy-seven patients were recruited, with 40 patients randomized to the early and 37 to the late patch group. The overall mean pre-operative Lysholm score was 51.8 (range 11-89) and significantly improved by 11.1 points (95% confidence interval [CI] = 4.8 to 17.4) at mean 12.7 years (range 1.5-23.7) follow-up. Latest mean Lysholm scores for the early and late groups were 68.4 (95% CI = 19 to 100) versus 56.7 (95% CI = 18 to 98). Adjusted for covariate imbalances, no evidence was found for a difference between the groups (mean difference = 8.5, 95% CI = -5.2 to 22.2, P = 0.22). Twenty-year survival until any re-operation or arthroplasty was 59.6%/82.1% for the early and 56.8%/69.5% for the late group, with no evidence for a difference.

Conclusion: ACI is an effective durable treatment for cartilage defects, with high levels of patient satisfaction and low failure rates. No evidence was found that applying the periosteal patch at the time of chondrocyte harvest improved long-term Lysholm scores or survival until any re-operation or arthroplasty.