A proximal fixed anatomic femoral stem reduces stress shielding

In 24 patients with total hip replacement using a short anatomic femoral st em, bone mineral density (BMD) was measured after a 7-year follow-up using dual-energy X-ray absorptiometry. The contralateral side was used as a cont rol. The BMD on the side of the prosthesis was lower by a mean of 7% than t hat on the control side. The difference was greatest in the area of the cal car and laterally and proximally around the stem. BMD at the metaphyseal an d diaphyseal areas were the same as on the contralateral side. The bone los s around the proximal aspect of the stem may be related to the proximal por ous coating. It is concluded that stress shielding can be diminished by app ropriate design of the femoral component.