Assessment of tibial torsion employing fluoroscopy, computed tomography and the cryosectioning technique.

Accurate assessment of tibial torsion, particularly the rotational deformity of a stabilized tibial fracture, demands precise anatomic landmarks at the proximal and distal measuring sites of the tibia. A fluoroscopic method has been proposed, utilizing the orientation of the femoral condyles and the medial malleolus to constitute two lines of reference. The relevance of using these structures for the assessment was studied while employing fluoroscopy, computed tomography, and the cryosectioning technique in 10 necropsy specimens of the human tibia. In all specimens the lines of reference were determined by each method and the tibial torsion was measured as the angle between the lines. The medial malleolus and the femoral condyles were found to present reliable anatomic landmarks for determination of the lines of reference in all employed techniques. The maximum difference between results obtained with different methods in a given specimen was 5.4 degrees. The average difference between results with two techniques and two observers varied from 1.0 to 1.5 degrees. The reproducibility of the fluoroscopic method, described by the estimated standard error of a single determination, was 1.3 degree.