Variations in bone mineral density of proximal femora of elderly people with hip fractures: a case-control analysis.

Background: Bone mass as represented by bone mineral density (BMD) is the most important factor determining bone strength. Elderly people with and without hip fractures were compared with the BMD of the proximal femora. The correlation between hip fractures in elderly patients and osteoporosis was investigated.

Methods: Eighty-seven consecutive elderly patients (≥65 years; average age, 77.5 years) with 87 unilateral hip fractures (39 femoral neck and 48 intertrochanteric fractures) were compared with 87 consecutive elderly persons (≥65 years; average age, 77.7 years) without hip fractures. Dual-energy X-ray absorptiometry was used to assess the BMD.

Results: The BMD of the total hip, greater trochanter, lesser trochanter, and femoral neck was significantly different between people with and without hip fractures (p = 0.002, 0.012, 0.011, and <0.001, respectively). All BMD values for patients with fractures were lower. Moreover, the BMD of the total hip, greater trochanter, lesser trochanter, and femoral neck was significantly different between people with intertrochanteric fractures and those without hip fractures (p < 0.001, <0.001, 0.003, and <0.001, respectively). Between patients with femoral neck fractures and those with intertrochanteric fractures, only the BMD value of the greater trochanter was significantly different (p = 0.04).

Conclusions: The severity of osteoporosis may affect the risk of hip fractures in elderly people. The risk of intertrochanteric fractures may be determined simply by BMD, but the risk of femoral neck fractures may be determined by multiple factors. Intertrochanteric fractures may start at the greater trochanter due to its low BMD.