Bone mineral density in patients with cervical and trochanteric fractures of the proximal femur

Abstract

The bone mineral density (BMD) of the proximal femur, spine and radius shaft was determined in 75 women with atraumatic fractures of the proximal femur (FXf) (average age: 70.1±9.6 years) and 51 controls of similar age. Fractures were classified as either cervical (n=36) or trochanteric (n=39) on the basis of radiographic and surgical finding. The BMD of spine and proximal femur was determined by dual-photon absorptiometry (Lunar DP3) and the BMD of the radius shaft by single photon absorptiometry. The BMD of patients with FXf was significantly decreased over all skeletal sites compared to controls of similar age. No significant correlation was found between age and the BMD of the femoral neck in patients with FXf. Patients with trochanteric FXf were older and thinner (average: age, 72.9±9.4 years; weight, 53.1±7.8 kg) compared with patients with cervical fractures (age, 67.2±8.9 years; weight, 59.3±8.3 kg). Likewise the BMD of trochanteric FXf was lower at all measured sites: femoral neck, 0.548±0.066 g/cm² vs 0.624±0.055 g/cm² (P2 vs 0.925±0.106 g/cm² (P2 vs 0.502±0.083 g/cm² (PP (Fisher)=0.0007). In summary, females with trochanteric FXf are older, thinner, have less bone mass in all measured sites and suffer with a significantly greater frequency of vertebral fractures. These patients have a generalized osteoporosis of the skeleton. Patients with cervical FXf seem to have more specific loss of the proximal femur (regional osteoporosis). The physiopathological process leading to trochanteric and cervical fractures is probably different.