This is a retrospective case-control study of arthroscopic partial meniscectomy for isolated lesions of the lateral meniscus, performed between 1990 and 1995. Thirty-one knees were evaluated after an average follow-up of 8 years: 48.4% had excellent/good IKDC-scores and 64.5% excellent/good Lysholm scores. The Tegner activity score dropped from 7.2 (competitive sports) to 5.7 (recreational sports). Fairbank changes were noted in 92.9% of the radiographs. Deterioration of results after arthroscopic partial lateral meniscectomy is obvious. The extent of the resection is a significant factor.