Hip fractures in the elderly: The role of cortical bone.

INTRODUCTION: Osteoporosis is characterised by poor bone quality arising from alterations to trabecular bone. However, recent studies have also described an important role of alterations to cortical bone in the physiopathology of osteoporosis. Although dual-energy X-ray absorptiometry (DXA) is a valid method to assess bone mineral density (BMD), real bone fragility in the presence of comorbidities cannot be evaluated with this method. The aim of this study was to evaluate if cortical thickness could be a good parameter to detect bone fragility in patients with hip fracture, independent of BMD.

METHODS: A retrospective study was conducted on 100 patients with hip fragility fractures. Cortical index was calculated on fractured femur (femoral cortical index [FCI]) and, when possible, on proximal humerus (humeral cortical index [HCI]). All patients underwent densitometric evaluation by DXA.

RESULTS: Average value of FCI was 0.43 and of HCI was 0.25. Low values of FCI were found in 21 patients with normal or osteopenic values of BMD, while low values of HCI were found in three patients with non-osteoporotic values of BMD.

DISCUSSION AND CONCLUSION: Cortical thinning measured from X-Ray of the femur identifies 21% additional fracture cases over that identified by a T-score <-2.5 (57%). FCI could be a useful tool to evaluate bone fragility and to predict fracture risk even in patients with normal and osteopenic BMD.