The medial meniscus was totally removed in 22 patients who were followed up for more than ten years. Preservation of the meniscal rims enhances regeneration. There was no evidence of medial compartment damage in 91% of the patients by arthroscopic examination at ten years' follow-up examination. This finding suggests that meniscal rim regeneration can protect the joint from osteoarthrotic changes. Late medial compartment osteoarthrosis following medial meniscectomy in an otherwise normal knee is probably avoidable if surgical and postoperative treatment are designed to enhance regeneration of the meniscal rim.