Non-simultaneous bilateral hip fracture: epidemiologic study of 241 hip fractures.

INTRODUCTION: Hip fractures are an important public health problem given their growing incidence as well as their functional and vital repercussions. With longer survival, patients with a contralateral fracture are increasingly numerous. The objective of this study was to investigate the bilateralization of hip fractures in terms of anatomic location and time to the second fracture.

HYPOTHESIS: Contralateral fractures are of the same anatomical type as the primary fractures.

PATIENTS AND METHODS: This was a retrospective epidemiological study on all patients managed for hip fractures between January 2007 and May 2008. Each case of bilateralization was studied.

RESULTS: We included 241 patients in the study. The mean age at occurrence of the primary fracture was 83.3 years (range, 60-99 years). The distribution showed 45.6% true femoral neck fractures and 54.4% trochanteric fractures. Twenty-six of the 241 patients had already suffered from a hip fracture (10.8%). This fracture was the same type as the recent fracture in 80.8% of the cases. The mean time between the two fractures was 5.6 years (range, 1-277 months).

DISCUSSION: The contralateral fractures were the same anatomical type as the primary fracture in eight out of ten patients and the symmetry remains intact in 64-83% depending on the series. The fracture occurred on average within 5 years of the first hip fracture. In cases of asymmetry, the second fracture was more often a trochanteric fracture. The causes explaining this symmetry are several and are poorly known. The risk factors are numerous and their prevention is essential (acting on the patient's environment to prevent falls, rehabilitation to reestablish autonomy after the first fracture, and preventive treatment of osteoporosis), although these notions are often ignored by surgeons.

LEVEL OF EVIDENCE: IV, retrospective study.