We retrospectively reviewed the long-term results of total meniscectomy performed in seventeen knees (fourteen children) to treat a discoid lateral meniscus. The mean duration of follow-up was 19.8 years (range, 12.5 to 26.0 years). On the basis of the rating system of the International Knee Documentation Committee, seven knees were normal (grade A), six were nearly normal (grade B), three were abnormal (grade C), and one was severely abnormal (grade D) at the latest follow-up evaluation. Ten of the seventeen knees had clinical symptoms of osteoarthrosis.Radiographs were available for fifteen of the knees at the latest follow-up evaluation. Eleven of the treated knees could be compared with the uninvolved, contralateral knee. Ten knees had osteoarthrotic changes, such as flattening of the lateral femoral condyle, formation of a ridge along the lateral femoral condyle, and spurring and sclerosis of the tibial plateau. Osteochondritis dissecans in two knees, nine and twenty years after the initial meniscectomy.