Outcomes of autologous chondrocyte implantation in a diverse patient population.

BACKGROUND Autologous chondrocyte implantation is indicated as a second-line treatment of large, irregularly shaped chondral defects after failure of first-line surgical intervention. This study examines the clinical results of a patient cohort undergoing autologous chondrocyte implantation and elucidates factors associated with subjective improvement after implantation. HYPOTHESIS Autologous chondrocyte implantation will result in long-term functional and symptomatic improvement. STUDY DESIGN Case series; Level of evidence, 4. METHODS The cohort included 137 subjects (140 knees) who underwent autologous chondrocyte implantation of the knee. Mean defect size per patient was 5.2 +/- 3.5 cm(2) (range, 0.8-26.6 cm(2)). Patients averaged 30.3 +/- 9.1 years of age (range, 13.9-49.9 years) and were followed for 4.3 +/- 1.8 years (range, 2.0-9.7 years). Outcomes were assessed via clinical assessment and established outcome scales, including the Lysholm scale, International Knee Documentation Committee scale, and Short Form-12. RESULTS A significant improvement after surgery was observed in all outcome assessments including the Lysholm (41 to 69; P < .001) and International Knee Documentation Committee (34 to 64; P < .001) scales. Subjectively, 75% of patients indicated they were completely or mostly satisfied with the outcome and 83% would have the procedure again. Preoperatively, 32% of patients had a Tegner score of 6 or greater, compared with 82% before injury and 65% at most recent follow-up. Multivariate analysis identified age (P < .021) and receiving workers' compensation (P < .018) as independent predictors of follow-up Lysholm score. Twenty-one patients (16%) required debridement of the autologous chondrocyte implantation site secondary to persistent symptoms, whereas 9 knees (6.4%) clinically failed and underwent a revision procedure. CONCLUSION Autologous chondrocyte implantation is a viable treatment option for chondral defects of the knee, resulting in durable functional and symptomatic improvement. Age and workers' compensation status are independent predictors of outcome.