Bone loss around failed femoral implant measured by dual-energy X-ray absorptiometry.

Periprosthetic bone mineral density (BMD) and its changes after primary total hip arthroplasty (THA) have been studied extensively, but quantitative data on BMD around loosened prostheses are still lacking. In this study, using dual-energy X-ray absorptiometry (DXA), we determined periprosthetic BMD in 19 patients with failed primary THA. There was a decrease in BMD (8. 8%-25.5%) in every Gruen zone as compared with the patient's non-operated (control) side. Although the bone loss was most significant in the proximal femur, as in primary THA, the pattern of bone loss around the failed THA differred from the typical remodeling seen after successful THA. We suggest that quantitation of bone mass around the failed femoral stem is possible. Remarkable generalized bone loss around the stem is associated with a loosened prosthesis.