Femoral Neck Shaft Angle in Men with Fragility Fractures

S. P. Tuck,D. J. Rawlings,R. M. Francis,A. D. Woolf,G. D. Summers,I. Pande,A. C. Scane

doi:10.4061/2011/903726

Abstract

Introduction. Femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk in men. We aimed to assess the role of NSA in UK men. Methods. The NSA was measured manually from the DXA scan printout in men with hip (62, 31 femoral neck and 31 trochanteric), symptomatic vertebral (91), and distal forearm (67) fractures and 389 age-matched control subjects. Age, height, weight, and BMD (g/cm2: lumbar spine, femoral neck, and total femur) measurements were performed. Results. There was no significant difference in mean NSA between men with femoral neck and trochanteric hip fractures, so all further analyses of hip fractures utilised the combined data. There was no difference in NSA between those with hip fractures and those without (either using the combined data or analysing trochanteric and femoral neck shaft fractures separately), nor between fracture subjects as a whole and controls. Mean NSA was smaller in those with vertebral fractures (129.2° versus 131°: P = 0.001), but larger in those with distal forearm fractures (129.8° versus 128.5°: P = 0.01). Conclusions. The conflicting results suggest that femoral NSA is not an important determinant of hip fracture risk in UK men.

Highlights

Femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk in men
This has been most extensively studied in women at the hip, in terms of hip axis length (HAL), femoral neck axis length (FNAL), neck shaft angle (NSA), and femoral neck width (FNW)
The vertebral fracture study demonstrated any significant height differences between fracture and control subjects, presumably because of height loss associated with vertebral fractures

Summary

Introduction

Femoral neck shaft angle (NSA) has been reported to be an independent predictor of hip fracture risk in men. Bone mineral density (BMD) has long been recognised as an important skeleton determinant of fracture risk, but it is becoming apparent that skeletal geometry influences the risk This has been most extensively studied in women at the hip, in terms of hip axis length (HAL), femoral neck axis length (FNAL), neck shaft angle (NSA), and femoral neck width (FNW). The role of all of these factors as independent predictors of hip fracture risk is controversial in both sexes, with studies giving conflicting results [5, 6] This uncertainty may have arisen partly because of differences in study design, numbers of patients studied, and because of wide variations in geometric parameters in different countries and races [7, 8]. It did not measure NSA or femoral neck width, so there is a need for further study of the role of femoral geometry in men

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