Objective: To compare the respective performance and effectiveness of autologous chondrocyte implantation (ACI) and mosaicplasty at resurfacing local full-thickness chondral defects of the knee.
Design: Randomized clinical trial.
Setting: Multicenter trial at orthopedic clinics and university hospitals conducted from 1997 to 2000.
Patients: A population of patients selected according to eligibility criteria of age, traumatic origin of the defect, its localization, size, and gravity, and above all, no previous surgical treatment of the lesion. Forty-seven patients were randomly assigned to ACI or mosaicplasty and subjected to arthroscopic debridement of the lesion at the time of enrollment. They were called for surgery 6 months after the initial debridement.
Main outcome: Improved knee functionality as assessed by repeated clinical evaluation based on the International Knee Documentation Committee Scale and the Lysholm Knee Scoring Scale.
Results: Fourteen patients (31.8%) experienced substantial improvement following the initial debridement and, being clinically cured, received no further treatment. Seven patients (15.9%) were lost to follow-up. Among the 23 patients (52.3%) who could effectively be evaluated, a complete recovery (ie, Lysholm Knee Scoring Scale score, 90-100) was observed upon clinical examination in 88% of the mosaicplasty-treated patients and in 68% of the ACI-treated ones (P = 0.093).
Conclusions: Although the low power of our study prevents definitive conclusions, ACI and mosaicplasty are cartilage repair techniques that are clinically equivalent and similar in performance. The high percentage of spontaneous improvement ((1/3) of the patients) observed after simple debridement calls into question the need for prompt surgical treatment of patients with lesions similar to those included in this clinical trial. Moreover, this finding warrants further investigation, ideally through randomized clinical trials in which patients subjected to debridement alone are compared with patients undergoing reconstructive surgery.