Changes in bone mineral content in the femur following total hip arthroplasty.

Bone mineral content (BMC) in the distal end of the femoral shaft was monitored with single-photon gamma-absorptiometry for 72 weeks after surgery in 46 patients with coxarthrosis treated by total hip arthroplasty (THA). After an initial increase, which was greater in men than in women, BMC decreased during the first postoperative year to approximately the initial value in men, whereas in women the final outcome was a 10% net loss. No influence of the type of operation or of the preoperative or postoperative capacity of the patients could be demonstrated. The loss of bone mineral was surprisingly low compared with that noted after other injuries of similar or even less magnitude.