Longitudinal changes in bone mineral density in patients following total hip replacemen

This thesis presents data on a one-year study of the relative effects of total hip replacement surgery on the bone mineral density (BMD) in ten osteoarthritic patients (three males + seven females), aged 49 to 81 years.;Bone mineral density (BMD) in the lumbar spine (L$sb1$ to L$sb4$), and in the proximal femur (neck, trochanter, intertrochanteric region, and Ward's triangle) was measured using dual energy x-ray absorptiometry (DEXA). BMD measurements were made for each subject at baseline (one month before surgery), and at 4 and 12 months after surgery.;Bone biopsies from the intertrochanteric region of the femur were obtained intraoperatively and processed for the evaluation of histomorphometric variables. Biochemical data collected at baseline included: 25-hydroxy vitamin D, parathyroid hormone, total proteins, serum ionized calcium, and serum alkaline phosphatase.;At baseline, BMD measurements and bone histomorphometric variables did not show a significant correlation, but a strong correlation was observed between BMD measurements and biochemical data.;For all subjects, BMD in the spine and proximal femur at 4 and 12 months were not significantly different from baseline. In 4 of 10 patients, however, BMD in the spine was significantly different between baseline and 4-months, and also between 4-months and 12-months.;These data suggest that the new biomechanical status following total hip replacement may have a positive effect on BMD in the lumbar spine.