Arthroscopy of the painful failed total knee arthroplasty has rarely been reported. The indications and results in terms of diagnosis and treatment of pathologic conditions in 13 knees after total knee arthroplasty are reviewed. Arthroscopy established the diagnosis for pain in 12 of 13 knees. Several problems were commonly encountered, including arthrofibrosis and fracture of the polyethylene button. Arthroscopic surgery for arthrofibrosis was successful in improving range of motion and knee-rating score.