Schwarz T, et al. - Authors estimated the cup position and acetabular parameters by assessing pelvic tilt in AP radiographs using tilt ratios. They calculated tilt ratios by means of the two parameters (the height of the lesser pelvis and the obturator foramen) in simulated radiographs for ten male and ten female pelvises in defined tilt positions. Their method of assessing pelvic tilt in AP radiographs could improve the analysis and interpretation of cup position and acetabular parameters. Findings suggested that for each 5° step of simulated pelvic tilt no differences were found between male and female tilt ratios. An exponential correlation between pelvic tilt and tilt ratios was seen.