Assessment of bone mineral at appendicular sites in females with fractures of the proximal femur

Abstract

The prediction of hip fractures by measurements at remote sites or the improvement of predictive power by measurements at multiple sites could potentially increase the success of osteoporosis screening programs. In a cross-sectional study on 137 postmenopausal women, we tested the hypothesis that bone assessment at the hip, the forearm, and the tibia are independently associated with osteoporotic fractures of the hip. Bone mineral densities, geometric features, and ultrasound properties were determined with hip dual X-ray absorptiometry, forearm peripheral quantitative computed tomography (QCT), and tibia speed of sound measurement. While the odds ratios for fracture discrimination per standard deviation decrease ranged between 3 and 4 for measurements at the hip, they were only 1.8 at the forearm and 1.4 at the tibia. Measurements at the tibia or the forearm were neither independently associated with osteoporotic hip fractures (p > 0.05) nor could any combination of measurements significantly increase the power for the identification of fractures as measured with receiver operating curves. Women who sustained trochanteric fractures were characterized by a generalized loss of bone mineral. Cervical fractures were associated with a decrease of bone mineral density at the hip, but no significant alterations in bone mass or geometric properties were observed at the tibia or at the forearm. Fracture risk prediction at the hip is therefore preferably performed by measurements at the hip itself. Peripheral QCT at the distal radius and tibial ultrasound seem capable of depicting women with an increased risk for trochanteric but not for cervical fractures. The risk assessment appears not to be improved by including information of cortical or geometric properties of the forearm.