Thirty-one knees with symptomatic total knee arthroplasty were diagnosed and treated arthroscopically. There were 18 knees with soft tissue impingement and 13 knees without. There were 16 knees with painful arthroplasty and range of motion (ROM) greater than 90 degrees. Hypertrophied synovitis with or without impingement was more easily found by arthroscopy in this group than in the other 15 knees with the chief complaint of limited ROM, where more remarkable fibrotic tissue with intra-articular adhesion was found. Overall, the average improvement in ROM was 43.1 degrees immediately after arthroscopy, and 20 degrees at the final follow-up. Symptoms improved in 90.3% of patients, and 58.1% were satisfied with the outcome of their surgery. Arthroscopy is helpful for intra-articular diagnosis, obtaining a specimen for histopathologic analysis, culture for subclinical infection, and better improvement in ROM. In our experience, arthroscopy for symptomatic knee arthroplasty is reliable, safe and effective.