Figure 1.

The limb length was evaluated by measuring the perpendicular distance (mm) between the teardrop and the lesser trochanter. The difference between the left and right side constituted the leg length difference. For evaluation of the cup inclination we measured the angle between the teardrop line and the long axis of the ellipse, which presents itself as the acetabular opening on the radiograph. The anteversion of the cup was calculated as inverse sine function of the ratio of short to the long axis of the acetabular cup. To determine the precision of stem positioning, the angle between the axis of the bony femoral shaft and the implanted stem was measured.