Bone mineral density 10 years after a Zweymüller uncemented stem prosthesis

The effect of a Zweymüller uncemented stem prosthesis on the long-term bone remodelling of femoral bone was examined using dual-energy X-ray absorptiometry (DEXA). Thirty-two patients (11 males, 21 females) with a unilateral prosthesis (18 Hochgezogen and 14 Stepless) were scanned at an average of 129.8 months after the initial operation. The average follow-up Harris Hip Score was 93.7: ten patients were classified as Charnley Class A, two patients as class B and 20 patients as class C. The group as a whole showed a moderate activity level and most patients were satisfied with the result of the operation. All stem prostheses were osseo-integrated. The non-operated contralateral femur was used as a control for the bone mineral density (BMD) changes in the femur around the prosthesis. A decrease of bone mineral density on the prosthesis side was found at the region of the calcar femoris, without any clinical decline or any radiographic anomalies.