The long-term effects of single meniscectomy in 89 children have been analyzed at an average of 16.8 years after surgery. Seventy-four percent were pleased with the outcome, but only 52% or 58% had objectively satisfactory results according to the two scoring systems used. Significantly poorer results were achieved with lateral meniscectomies. The range of movement was significantly decreased after lateral meniscectomy. Minor instabilities were recorded in 45% of the patients and major instabilities in 15%. Anteroposterior and rotatory instabilities were objectively measured, and a significant increase was noted in knees that had lateral meniscectomy. Grade I gonarthrosis was recorded in 39% of the surgically treated knees and Grades II and III gonarthroses in 9%. The joint space was significantly reduced in all knees irrespective of the injured compartment.