BONE-MINERAL DENSITY-MEASUREMENT OF THE P ROXIMAL FEMUR IS INFLUENCEDBY FEMORAL-NECK ANTEVERSION AND ROTATION

The DEXA-method allows for bone mineral density measurements of differ ent 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; similarl y biased results can be expected at the proximal femur due to morphome tric peculiarities. The influence of anteversion and rotation of the f emoral neck has been investigated in the present study. The results in dicate that errors due to rotation as occurring in incorrect positioni ng or in arthrogenic variabilities mainly have effects on measurements of Ward's triangle: The average measurement error at 20 degrees exter nal rotation amounts to 33.8% with a maximum of 66.5%. Measurements of the trochanteric region and of femoral neck region show a variation o f 6.2% and 9.7%, respectively.