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

Hip fractures can be separated into femoral neck (cervical or intracap sular) or trochanteric (extracapsular). Trochanteric fractures have be en associated with up to twice the short-term mortality of cervical fr actures in the elderly. Fracture type may be influenced by the fall di rection and local differences in proximal femur strength properties. W e previously demonstrated that fall characteristics and body habitus, in addition to femoral bone mineral density, play a dominant role in t he prediction of hip fracture in elderly fallers. To examine the assoc iation 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 troc hanteric fracture than in those with femoral neck fracture (p < 0.01). A stepwise multiple logistic regression indicated that trochanteric B MD (decrease of 1.0 SD, adjusted OR 4.6, 95% Cl 2.0-9.5, p < 0.0001) a nd 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 fractu re. Fall characteristics, body habitus, gender, and age were not assoc iated with hip fracture type. We conclude that a relatively low trocha nteric BMD or a high femoral neck BMD was associated with a trochanter ic hip fracture and that site-specific trochanteric BMD determinations should be measured when assessing risk of trochanteric hip fractures in the elderly.