Computed tomography in the determination of leg geometry.

In 286 adults with misalignment of the lower limb the length and torsional angles of the femur and tibia were determined using a method based on computed tomography. Depending on the location of the axial scan values for femoral antetorsion changed substantially. Normal values obtained in non injured extremities by this technique were an internal torsion of 23.5 +/- 8.6 degrees (mean +/- SD) in the femur and an external torsion of 34.9 +/- 8.6 degrees in the tibia. Mean intraindividual side differences in the femur and tibia were 4 degrees, the 95% confidence interval was 11.0 degrees in the femur and 12.3 degrees in the tibia. CT-methods can only be used for the determination of torsional angles in the femur and tibia if reproducible and standardized locations for the acquisition of axial scans are defined.