Results of total knee arthroplasty are uniformly good. There is, however, a certain subset of patients who, despite an excellent radiographic result, do not do well. From 1992 through 1994, 20 patients were referred for pain and disability after total knee arthroplasty with normal appearing office radiographs. Fluoroscopic radiographs were obtained after other causes of disability were excluded. In 14 of the 20 patients, the diagnosis of aseptic loosening was made with fluoroscopically guided radiographs. Each patient thought to have a loose component at fluoroscopy did, in fact, have a loose component at revision. Each patient improved after revision with an average increase in the Hospital for Special Surgery score of 26 points. Fluoroscopically guided radiographs can be helpful in evaluating the patient with a painful total knee arthroplasty and normal appearing office radiographs.