Incidence of bilateral proximal femoral fractures in a tertiary care center.

Over a 7-year period, a total of 545 osteoporotic fractures involving the proximal femur were treated at our institution. Twenty-nine patients sustained fractures of both hips, representing an overall incidence of bilateral hip fractures of approximately 5.5%. Of the 29 patients with bilateral hip fractures, adequate records and radiographs were avaialable for 28. There was a significant similarity between fracture patterns in the majority of bilateral hip fracture patients: 18 (64%) patients demonstrated similar fracture patterns on both sides. In these 18 patients, the average interval between fractures was approximately 1.7 years; in the remaining 10 patients, in whom the fractures were of dissimilar nature, the average interval between fractures was approximately 3.5 years. These findings suggest that at least 1 in 20 patients who sustain a fracture about the hip can expect to suffer a fracture involving the contralateral side. Moreover, the difference in the average interval for fractures of similar nature compared to fractures of dissimilar nature suggests the effects of physiologic age and the accordant changes in bone architecture play a larger role in predicting subsequent fracture pattern.