TROCHANTERIC BONE-MINERAL DENSITY IS ASSOCIATED WITH TYPE OF HIP FRACTURE IN THE ELDERLY

Hip fractures can be separated into femoral neck (cervical or intracapsular) or trochanteric (extracapsular). Trochanteric fractures have been associated with up to twice the short-term mortality of cervical fractures in the elderly. Fracture type may be influenced by the fall direction and local differences in proximal femur strength properties. We previously demonstrated that fall characteristics and body habitus, in addition to femoral bone mineral density, play a dominant role in the prediction of hip fracture in elderly fallers. To examine the association of these determinants with hip fracture type, we assessed fall characteristics, body habitus, and site-specific bone mineral density measurements in 112 elderly hip fracture patients (85 women and 27 men, mean age 85 years) 1 week after an acute hip fracture. Trochanteric BMD was 13% lower in women and 11% lower in men for patients with trochanteric fracture than in those with femoral neck fracture (p < 0.01). A stepwise multiple logistic regression indicated that trochanteric BMD (decrease of 1.0 SD, adjusted OR 4.6, 95% Cl 2.0-9.5, p < 0.0001) and femoral neck BMD (increase of 1.0 SD, adjusted OR 3.0, 95% Cl 1.6-5.9, p = 0.0003) were independently associated with trochanteric fracture. Fall characteristics, body habitus, gender, and age were not associated with hip fracture type. We conclude that a relatively low trochanteric BMD or a high femoral neck BMD was associated with a trochanteric hip fracture and that site-specific trochanteric BMD determinations should be measured when assessing risk of trochanteric hip fractures in the elderly.