Fig. 3.

Measurement of anteversion with femoral head of size 50 % (a) and 66 % (b) of that of the acetabular cup. A perpendicular is dropped from the visible part of the ellipse to its diameter to intersect the diameter and the outline of the acetabular cup at points O and E, respectively. Distance OE (a’) is measured and a point X is marked on the long diameter at a distance of OE from point D. The angle DXO is the angle of anteversion. Measurement of anteversion in uncemented total hip replacement using only the visible part of acetabular ring (c)