Arthroscopic Treatment of Discoid Lateral Meniscus in Adults

41 discoid lateral menisci (DLM) in 34 adults over 20 years of age were operated arthroscopically from 1994 to 2000. They complained of knee pain, lack of extension, hydrarthrosis, etc. 29 knees (71%) were not associated with specific injuries, and in 30 knees (73%) more than 4 weeks had passed since the symptoms occurred. Excluding 9 worn menisci in 6 patients, DLM were classified as incomplete (69%) or complete (31%). Evaluation of articular cartilage was rated on the basis of the Fujisawa classification system, and there were more degenative changes on the lateral compartment than the medial. 19 knees (46%) underwent total menisectomy, 10 knees (24%) subtotal menisectomy, and 12 knees (29%) partial menisectomy. From preoperative radiographs of 34 DLM in 28 patients, 18 DLM (52%) were diagnosed as osteoarthritis.26 DLM in 14 patients were surveyed by interview or telephone. The average duration of follow-up was 40.3 months (8-82 months). Evaluation of clinical results was rated on the basis of the modified Amako classification system postoperatively, and 22 knees (72%) had either A (excellent) or B (good) ratings. Though we investigated the factors for unsatisfactory clinical results, degeneration of cartilage on the lateral seemed to reflect clinical results.