Fig. 2.

Measurement of the native and stem version. The axis of the femoral neck was calculated as the best-fit line in slices taken through a central segment of the neck. Native femoral version was defined as the angle formed between the axis of the neck and a line connecting the posterior aspect of the medial and lateral femoral condyles (a, b). A base line was defined as a line connecting the posterior aspect of the medial and lateral femoral condyles. Stem version was calculated as the angle of the prosthetic femoral neck relative to the posterior condyles of the knee (a, c)