Mosaic osteochondral transplantations in the knee joint, midterm results of the SFA multicenter study

Introduction: There are several possible options to treat focal articular cartilage defects of the knee. The aim of this study was to evaluate the results and prognostic factors cartilage defects of the knee treated by autologous osteochondral mosaicplasty after more than five years of follow-up.

Patients and methods: One hundred forty-two cases were included in this retrospective multicenter study. Etiologies included osteochondral fractures (n=79), and osteochondritis dissecans (n=61). Mean age of patients was 31. There was a majority of men (76%). Mean BMI was 25 (range: 21-41). Fifty-three percent of the knees had a history of surgery. Mean delay between the accident and surgery was 2.5 years. Mean area of the defect was 2.29 cm(2) (range: 0.3-12.25 cm(2)). The depth of the defect was 3 or 4 on the ICRS score in 97% of cases. An additional surgical procedure was associated with mosaicplasty in 14% of the cases. The follow-up evaluation was based on the Hughston score, the ICRS score, the IKDC subjective score, and the IKDC radiological score. Evaluation of control MRI was based on a modified MOCART score.

Results: The mean follow-up was 96 ± 28 months. There were complications in 19 patients. Patients were able to begin athletic activities again after a mean 35 weeks. Most patients (81.8%) were satisfied or very satisfied. There was a significant improvement (p<0.001) in the ICRS, IKDC function and Hughston scores at follow-up. The factors for a good prognosis were: male gender, medial femoral condyle defects, osteochondritis dissecans, deep, small defects, and the shortest possible delay to surgery. Obesity, smoking, work-related accidents, the level of sports practiced, the percentage of coverage of the defect, the number of plugs, and associated lesions did not have a statistically significant effect on the functional results in the final follow-up.

Discussion: Autologous osteochondral mosaicplasty seems to be a reliable technique in the short and intermediate term. It has the advantage of being less expensive than reconstructive techniques, is a one-step surgical procedure and results in immediate restoration of cartilage surface. Nevertheless, this is a difficult technique, which may result in complications and requires articular harvesting. This technique is limited by the size of the defect to be treated. The primary indication is deep, small defects on the medial femoral condyle.