Technique of torsion measurement of the lower extremity using computed tomography.

Axial CT is the most accurate and convenient technique for the measurement of lower limb torsion; its accuracy is equal to that of cadaveric skeletal measurement. Both extremities are examined simultaneously, and the comparison of the right and the left leg provides the most important value. The torsion angulation is obtained directly by superimposing the magnified image of each scan on the other. Patient positioning is comfortable and a relatively short examination time is required. It does not require special equipment or skill on the part of the examiner. The radiation dose appears to be lower than that of the conventional radiographic method.