Zones of impingement-free compliant stem/cup orientation under the influence of (initial) Femoral Tilt. Left side: iFT = 2.1°, right side: iFT = 9.3°. In both cases the effective antetorsion (AT) is set to 15° and NSA = 135°, VV = 4.5°. The zone-of-compliance is more than 200% smaller for iFT = 9.3°. The optimum cup position according to Widmer (marked by a circle) changes from 35° radiographic inclination / 30° anteversion to 39° inclination / 30° anteversion.