Acetabular Retroversion: Dysplasia in Disguise that Leads to Early Arthritis of the Hip

We aimed to assess the prevalence of acetabular retroversion (AR) in patients undergoing total hip replacement (THA) based on age. We retrospectively compared preoperative anteroposterior pelvic radiographs of patients younger than 40 years of age who underwent THA with the age- and body mass index-matched control of 40 years and older patients. Retroversion was determined based on the presence of cross-over sign, ischial spine sign, posterior wall sign, and elephant's ear sign with data stratified based on presence of dysplasia.