Radiologic diagnosis of loosening and infection in hip prostheses.

Unexplained pain following prosthetic replacement of the hip should be evaluated by a review of serial plain radiographs, hip aspiration and arthrography. The distinction between infection and loosening cannot be established on plain films. The preoperative diagnosis of infection and/or loosening should be attempted by hip aspiration and arthrography. Neither of the latter studies is definitive but in combination they correlate well with the surgical findings.