Fig. 3.

Line T designates the transteardrop line. Line XY designates the transverse acetabular ligament. The mouth of acetabulum is from the midpoint of Line XY (point A) to the superior-lateral cortical rim of the acetabulum excluding osteophytes (point B). Point Z marks the midpoint of Line AB. Line ZD is 7 mm lateral and perpendicular to point Z. The center of the acetabulum (point C) is 1 mm cranial to point D. The center of the femoral head (F) was determined by using a transparent template with concentric circles. Line CE is drawn parallel to the transteardrop line from point C to point F. The change necessary to make the centers of rotation C and F coincide in the lateral direction (offset) is Line CE and the vertical direction (hip length) is Line FE.