Long-Term Results of Abrasion Arthroplasty for Full-Thickness Cartilage Lesions of the Medial Femoral Condyle

Abstract

To evaluate the long-term functional results of arthroscopic abrasion arthroplasty for the treatment of full-thickness cartilage lesions of the medial femoral condyle. Between 1990 and 1996, 75 consecutive patients with isolated chondral lesions of the medial femoral condyle were treated with arthroscopic chondral abrasion. A retrospective analysis of the clinical results of this cohort was performed. The patients were evaluated according to the Knee Society Score questionnaire preoperatively, at 10 years postoperatively, and at final long-term follow-up at a mean of 20 years. At final follow-up, they were also assessed according to the Western Ontario and McMaster Universities Osteoarthritis Index. Patients were divided according to the lesion size and by age, and the Kaplan-Meier survivorship function (with second operation taken as an endpoint) for the various groups was calculated. At a mean of final follow-up of 20 years (range, 16.94 to 23.94 years), a positive functional outcome (Knee Society Score ≥70 points or no reoperation) was recorded in 67.9% of the patients. Twenty-year survivorship in this cohort was 71.4% (95% confidence interval, 0.5690 to 0.8590). The survivorship was 89.5% for patients younger than 50 years and 55.7% for patients aged 50 years or older. The functional results for patients with lesions smaller than 4 cm(2) were significantly better than those for patients with lesions of 4 cm(2) or greater (P = .031). There were no statistical differences between patients with and without associated lesions at the time of surgery. Our hypothesis that there would be survivorship greater than 86% was disproved. However, arthroscopic abrasion arthroplasty can be a valid treatment for medial femoral condylar full-thickness defects of the knee, even in the long-term, particularly for younger patients and those with smaller lesions. Level IV, therapeutic case series.