Prosthetic hip replacements: plain films and arthrography for component loosening.

Component loosening of prosthetic hip replacements was evaluated solely by plain films in 56 patients and solely by arthrography in 49. Radiographic results and surgical findings were compared in all cases. Arthrography was associated with fewer errors. For acetabular component loosening, there were 11% fewer errors made by arthrography (26% versus 15%). However, for femoral component loosening, the number of errors decreased by only 3% (15% versus 12%). The errors associated with evaluation of the acetabular component were predominately false-positive, both on plain films and arthrography. For femoral component evaluation, plain films and arthrography were predominately associated with false-negative errors.