The long-term results after partial arthroscopic meniscectomy were evaluated in follow-up examinations on 77 patients performed according to identical criteria after post-operative periods of two (6-36 months) and seven years (66-96 months). The subjective results after up to more than seven years showed a stable course and were unrelated to the radiological signs of osteoarthritis. The objective clinical results, assessed in the Lysholm score, showed a significant deterioration as compared to the two-year follow-up (p < 0.0002). In particular, an obvious increase of pain and an increased tendency for swelling were observed, while the results in the Lachman test showed a significant reduction of anterior instability (p < 0.0015) as an obvious result of a marked improvement of muscle strength. These results also correlated with a significant increase of sporting and exercise capacity as compared to the results obtained in the two-year follow-up. While osteoarthritis rates seen in the first follow-up were similar to the preoperative findings, a massive increase of osteoarthritis could be seen at the second follow-up after a further five years with only 22 of 77 patients (28.6%) showing no radiographic signs of osteoarthritis. In 31 patients (40.25%) with negative preoperative findings slight to moderate signs of osteoarthritis were seen in the seven-year follow-up. Regardless of the type of meniscal tear the osteoarthritic changes seen were related to the age of the patient and the stability of the joint and were significantly different from those in the non-operated, contralateral joint.(ABSTRACT TRUNCATED AT 250 WORDS)