Measurement of periprosthetic bone mineral density after hip arthroplasty

Objective To measure the periprosthetic bone mineral density (BMD) after uncemented hip arthroplasty by applying the upgraded Dual energy X ray absorptiometry (DEXA) method. Methods Forty six patients who had the hip replaced in our hospital in recent 5 years were studied. All the patients had X ray and the BMD of both femurs were measured with the upgraded DEXA method. Results The BMD decreased rapidly in the first year after operation, but patients with higher BMD lost less bone. The BMD in the medial part of the stem and in the trochanter decreased most, the bone at the lateral part of the stem lost less, and at the tip of the stem the lest. The collar of the stem could reduce bone loss at the calcar region. The gender, age and weight, all these factors were not related with the bone loss. Conclusions The upgraded DEXA is a precise and reliable method in clinical follow up after hip arthroplasty.