Abstract
We performed repeated dual-energy X-ray absorptiometry (DEXA) measurements over five years in a homogeneous patient population to study the effect of a cemented stem on proximal femoral bone remodelling. Data from 88 patients (88 hips) implanted with total hip arthroplasty (THA) prostheses were extracted from three randomised studies. Femoral bone mineral density (BMD) was measured using a Lunar DPX-IQ densitometer for five years postoperatively. At one year the BMD changes had decreased between -2.0% [region of interest (ROI) 1] and -11.5% (ROI 7). During the follow-up period the BMD initially increased during the second year and thereafter decreased again in ROIs 5, 6 and 7. The loss of BMD at five years was more pronounced in region 7 (12.9%) and decreased with increasing age, total hip replacement (THR) on the right side and decreasing weight of the patient. We found that after the initial phase of early bone loss a period of recovery follows. Thereafter the BMD decreases again, which probably reflects the normal ageing of bone after uncomplicated cemented THA.