DUAL X-RAY ABSORPTIOMETRY FOR THE EVALUATION OF BONE-DENSITY FROM THEPROXIMAL FEMUR AFTER TOTAL HIP-ARTHROPLASTY - ANALYSIS PROTOCOLS AND REPRODUCIBILITY

Dual X-ray absorptiometry (DXA) instruments are now able to evaluate b one mineral density (BMD) of bone surrounding metal implants. The asse ssment of BMD around prosthetic components could provide additional in formation for the follow-up of total hip arthroplasty (THA). In this s tudy, we evaluated the potential application of DXA in the field of TH A. BMD was measured in the proximal femur of both THA and THA-free sid es in 14 postmenopausal women 6-18 months after THA. The explored segm ent was divided into seven zones as proposed by Gruen et al. [18]. The precision error of BMD measurements ranged from 1.8 to 6.8% on the TH A side and from 1.1 to 2% to the THA-free side. The reduction of BMD o f the THA versus the THA-free side was significant in all seven zones (P < 0.01, t-test for paired data). These results showed significant d ifferences in BMD around femoral components of THA with respect to con tralateral healthy side, and demonstrate the sensitivity of DXA for de tecting these changes.