Does Bone Mineral Density Affect Hip Fracture Severity?

The association between hip fracture and reduced bone mineral density is well documented, with reduced bone mineral density predisposing to fracture. However, it is unknown whether an association exists between the magnitude of bone density lost and the severity of the hip fracture sustained. One hundred forty-two patients (96 women, 46 men) with a mean age of 74 years (range, 49-92 years) who sustained a hip fracture following a simple ground-level fall and were treated for this injury were reviewed. All patients had undergone dual-energy x-ray absorptiometry bone scanning of the contralateral hip and lumbar spine. Fractures were classified as intra- or extracapsular or subtrochanteric and then subclassified by degree of severity as simple (stable) or multifragmentary (unstable) fracture patterns. Although a low hip bone mineral density (T- or Z score <2.5) was associated with an increased risk of extracapsular fracture (P=.025) compared with other fracture types, no association existed between bone mineral density and the severity of the resultant hip fracture. Although an association exists between bone mineral density and the risk of fragility fractures, the results of the current study suggest that the severity of hip fractures does not follow this correlation. Therefore, no assumption can be made about bone mineral density of the proximal femur based on the severity of the fracture observed on plain radiographs.