Thirty-five patients with limited extent of degenerative osteoarthritis of the femorotibial joint treated by arthroscope-guided surgery were compared after 1-3 years with 38 patients with a similar condition treated conservatively. In selecting a patient for arthroscope-guided surgery, the most important considerations were a normal mechanical axis, a limited extent of the degenerative process, and a femorotibial pain of sudden onset or that had been present for < 6 months. Clinical evaluation was undertaken using a modification of the Hospital for Special Surgery Knee Rating Score. The surgical procedure included partial meniscectomy, limited debridement of loose articular cartilage and removal of loose bodies. In the operated group, 26 patients (75%) showed improvement, five (14%) remained unchanged, and four (11%) were worse than before surgery. The average age of patients was 57 years. In the nonoperated group, six patients (16%) were improved, 12 (31%) unchanged, and 20 (53%) worse than before treatment. The average age of patients was 56 years. Arthroscope-guided surgery for limited degenerative osteoarthritis of the femorotibial joint with normal limb alignment or for degenerative meniscal tears has proven to be a useful technique.