Fig. 1

a Pelvic Tilt in 3D model. Pelvic tilt = the angle created by a line running from the first sacral midpoint to the symphysis pubis and a line perpendicular to the horizontal plane in the supine position. The normal value is about 60°. b Measurement of VA on Cross-table lateral Radiography. VA was measured using the following formula: anteversion = angle between a line along the rim of the cup and a line perpendicular to the horizontal plane. c Measurement of pelvic tilt from the lateral radiograph. d VA Measurements in 3D Simulation. Cross-table radiography was simulated by capturing a screenshot in the lateral position with rotation angles of 45°. PS. As the edge of the cup was obscured by the acetabulum, we reconstructed an acetabulum axis (the green component in the figure) for convenience and accuracy of measurement. e VA measurement on the transverse plane of 3D-transformed and PT-adjusted CT with the reference of posterior aspects of the ischium