Arthroscopic microfracture of chondral defects of the knee: A comparison of two postoperative treatments

Purpose: We hypothesized that the treatment of focal, full-thickness chondral defects by an identical method of arthroscopic microfracture but with different postoperative regimens would produce similar results. Type of Study: Case control study, retrospective cohort. Methods: Fifty patients treated over a 6-year period (1993 to 1999) with a focal, less than 2-cm², full-thickness chondral defect of either the medial or lateral femoral condyle of the knee had arthroscopic surgery to debride loose adjacent cartilage flaps and abortive fibrocartilage from the crater in conjunction with microfracture of the subchondral plate using a hand awl. Postoperatively, 1 group was treated with non-weight bearing and continuous passive motion (CPM) for 6 weeks (group I), and the other group was allowed weight bearing as tolerated and did not use CPM (group II). Results of treatment were assessed by the Lysholm knee rating scale augmented by the Tegner method of activity evaluation. Results were analyzed by independent t test or χ-square test with significance assumed for P <. 05. Results: Forty-three of 50 patients were evaluated at a minimum of 2 years after surgery (mean, 4.2 years; range, 2 to 9 years). The mean age was 39.7 years (range, 16 to 66 years) and there were 19 female and 24 male patients. For group I, Lysholm scores were 37 preoperative, 81 postoperative, and Tegner scores were 3 and 6, respectively. Group II Lysholm scores were 33 preoperative, 85 postoperative, and Tegner scores 3 and 6, respectively. No significant differences between groups were noted. Conclusions: In relatively small full-thickness chondral defects of the femoral condyles treated by microfracture, this study found no differences in results comparing 2 rehabilitation regimens differing by weight-bearing status and use of CPM. Level of Evidence: Level III, Case Control Study.