Fig. 1.

Measurement of CE angle, Sharp angle and AI. These angles were measured on a slice of femoral head center in the coronal plane. θ1, θ2, and θ3 is CE angle, Sharp angle and AI, respectively. CE angle was measured as the angle between the line joining the lateral aspect of the acetabulum and the femoral head center, and the line perpendicular to the line parallel to the transverse axis of the pelvis. Sharp angle was measured as the angle between the line joining the lateral aspect of the weight bearing zone and the inferior point of teardrop, and the line parallel to the transverse axis of the pelvis. AI was measured as the angle between the line joining the medial and lateral aspects of the weight bearing zone, and the line parallel to the transverse axis of the pelvis.