[Determination of rotation errors of the tibia using 2 standard roentgen images].

Radiological measurements of rotational deformities in the lower leg have so far only been possible by means of axial computerized tomography. In the present paper a method is described which also allows such measurements by the conventional X-ray procedure. The method requires only two complete X-ray pictures in two different planes of both lower legs, which have to be compared. No special standardized position of the legs is necessary during the X-ray procedure. The torsion angles of both lower legs and any inherent errors in measurement are evaluated by simple trigonometric calculation.