We reviewed 32 knees in 26 patients who had previously undergone arthroscopic debridement for symptomatic osteochondritis dissecans (OCD) of the knee. The patients were followed up at a minimum of 11 years following surgery and were evaluated clinically using the American Knee Society Clinical Rating Score. Additional evaluation was performed using the Hughston Scale to include radiographic assessment. The mean American Knee Society Score was 179 (out of 200), indicating good clinical function. Radiographically, however, only 29% scored excellent or good on the Hughston Scale. Younger patients with a small, stable (and therefore preserved), medial femoral condyle lesion had the best prognosis. Whilst more novel and complex options such as chondrocyte implantation are being assessed for the treatment of OCD, it is clear that within this study group careful debridement with removal of loose tissue can achieve good clinical results in the long term. There was however radiographic evidence of early degenerative joint disease in 17/24 (71%) of patients reviewed. Patients undergoing excision of OCD fragments did worse than those in whom the fragment was preserved, however the risk of further surgery is raised if a fragment is left in situ at initial surgery.