Slight abduction/adduction deviations in femur positioning for dual-energy X-ray absorptiometry are inconsequential

Abstract

Straight femur alignment during dual-energy X-ray absorptiometry (DXA) acquisition is assumed to help ensure accurate bone mineral density (BMD) measurement. Use of bilateral femur positioners may not result in straight femur alignment. To assess the effect of a bilateral femur positioner on DXA results, we compared a standard fixed-width bilateral femur positioner with an adjustable-width positioner that allowed for straight femur alignment. BMD values obtained from the adjustable-width bilateral femur positioner were highly correlated (R(2)=0.98-0.99) with those obtained using a fixed-width positioner. The mean bias in BMD between the fixed- and adjustable-width positioner was low (-0.001 to +0.006g/cm(2)) at all proximal femur regions of interest. In this study, the use of a fixed-width bilateral femur positioner and associated deviations in femur alignment have little consequence on BMD measurement.