Background: Osteoarthritis is common especially in over 50 years of age patients. There are several non–surgical treatment modalities such as non-steroid anti-inflammatory drugs, physiotherapy, and intra-articular injection of steroids and Hyaluronic Acid. Surgical procedures include arthroplasty, osteotomy of tibia and arthroscopic débridement. Careful selection of patients in particular, for arthroscopic débridement is a very important point.Methods: In a prospective study, 88 patients with mean age of 55.28 (55-63 years) with knee osteoarthritis who had failed non-surgical treatments were selected for arthroscopic débridement. Radiographic inclusion criteria were presence of 3-4 millimeters of joint space, less than 10 degrees flexion contracture and varus/valgus malalignment, and at least 100 degrees of flexion. The treatment results were assessed annually in 3 successive years, using Lysholm knee Scale. Seventy-four patients (43 females, 31 males) had complete follow-up and are reported here.Results: The pre operative Lysholm score of 37.2 (range: 26-55) increased to 81.9 (range: 70-90) in first year, to 82.9 (range: 70-95) by the second year and to 78.5 (60-90) in the third year (p < /em>