Arthrographic and radiologic evaluation of prosthetic joints.

Arthrography is indicated for the evaluation of a prosthetic joint for suspected infection, possible loosening based on clinical or plain radiographic findings, or unexplained pain following the insertion of a prosthesis. Interpretative difficulties most frequently occur when the acetabular component of the hip is evaluated. Also, the femoral component of a total knee arthroplasty is not optimally evaluated with arthrography. The decision to revise a loose prosthetic component is based on a clinical judgment. Arthrographic findings may facilitate this decision, but the decision does not depend solely on the arthrographic results. Rather, they must be evaluated in conjunction with other clinical and radiographic findings to eliminate false positive studies, thereby avoiding unnecessary surgery. In the presence of an equivocal arthrogram, radionuclide bone imaging shows promise as an adjunct for evaluating possible failure of a prosthetic component. It is also useful for evaluating the suspected failure of the femoral component of a knee prosthesis.