[Bone density measurements of the proximal femur in relation to torsion of the femoral neck].

The DEXA-method allows for bone mineral density measurements of different regions of the skeletal system. It is known that results obtained from the spine with this two-dimensional method may be biased in cases of spondylosis, spondylarthritis, and compression fractures; similarly biased results can be expected at the proximal femur due to morphometric peculiarities. The influence of anteversion and rotation of the femoral neck has been investigated in the present study. The results indicate that errors due to rotation as occurring in incorrect positioning or in arthrogenic variabilities mainly have effects on measurements of Ward's triangle: The average measurement error at 20 degrees external rotation amounts to 33.8% with a maximum of 66.5%. Measurements of the trochanteric region and of femoral neck region show a variation of 6.2% and 9.7%, respectively.