Femoral neck geometry and hip fracture risk: the Geelong osteoporosis study

Abstract

To determine the relationship between femoral neck geometry and the risk of hip fracture in post-menopausal Caucasian women, we conducted a retrospective study comparing the femoral neck dimensions of 62 hip fracture cases to those of 608 randomly selected controls. Measurements were made from dual-energy X-ray absorptiometry scans (Lunar DPX-L), using the manufacturer's ruler function, and included: hip axis length (HAL), femoral neck axis length (FNAL), femoral neck width (FNW), femoral shaft width (FSW), medial femoral shaft cortical thickness (FSCT(med)), and lateral femoral shaft cortical thickness (FSCT(lat)). The fracture group was older (median age 78.3 years vs 73.8 years), lighter (median weight 59.9 kg vs 64.5 kg), and, after adjustment for age, taller (mean height 158.7+/-0.8 cm vs 156.7+/-0.2 cm) than the controls. Furthermore, bone mineral density was lower in this group (0.682+/-0.016 g/cm(2) vs 0.791+/-0.006 g/cm(2)). After adjustment for age, bone mineral content (BMC) or height, hip fracture patients had greater FNW (up to 6.6%) and FSW (up to 6.3%) than did the controls. Each standard deviation increase in FNW and FSW was associated with a 1.7-fold (95% CI 1.3-2.3) and a 2.4-fold (95% CI 1.8-3.2) increase in the fracture risk, respectively. BMC-adjusted FNAL was greater in the fracture group (+2.1%) than in the controls, while the age-adjusted FSCT(med) was reduced (-7.2%). There was a trend towards longer HAL (up to 2.1%) after adjustment for age or BMC, and thinner age-adjusted FSCT(lat) (-1.7%) in fracture patients that did not reach statistical significance. In multivariate analysis, the risk of hip fracture was predicted by the combination of age, FNW, FSW, BMC and FSCT(med). HAL was not analyzed because of the small number of HAL measurements among fracture cases. We conclude that post-menopausal women with hip fractures have wider femoral necks and shafts, thinner femoral cortices and longer femoral neck axis lengths than do women with no fractures. Alteration in hip geometry is associated with the risk of hip fracture.

Association of Atypical Femoral Fractures with Bisphosphonate Use by Patients with Varus Hip Geometry

“…Proximal femoral strength is decreased with a varus mechanical axis 10,11 . Biomechanical studies have shown that trochanteric and femoral shaft fractures are more common in patients with low neck-shaft angles 12,13 . Koh et al reviewed the radiographs of forty-eight patients with atypical fractures and found that the fractures clustered in the lateral cortex at the region of maximal tensile loading 14 .…”

Effect of risedronate on hip structural geometry: A 1-year, double-blind trial in chemotherapy-induced postmenopausal women

“…Although some studies suggest that HSA provides significant additional information to BMD in predicting the occurrence of hip fracture [35][36][37], especially at the femoral neck [38], not all studies agree [39,34,40]. The latter studies suggest that HSA indices provide prediction of fracture risk, but might not contribute additional information beyond BMD.…”

Morphometric study of proximal femur in fractured and non-fractured post menopausal women

“…El-Kaissi et al [5] aimed to find out the relationship between femoral geometry and the risk of hip fracture in postmenopausal Caucasian women. Fractured patients had greater FSW and FAL than in controls.…”