Can Pelvic Orientation Be Accurately Predicted Using One Radiographic View Alone?

Pelvic positioning during total hip arthroplasty (THA) can affect the functional position of the acetabular component. A comprehensive understanding of pelvic orientation before THA is necessary to allow for proper cup positioning and mitigate the risks of postoperative complications. Measurements using anteroposterior (AP) radiographs have been described as an effective means of accurately predicting pelvic functional orientation. The purpose of our study was to describe the accuracy of assessing pelvic tilt using AP radiographs alone. An online survey was created and sent to a cohort of fellowship-trained adult reconstruction (AR) surgeons. The survey consisted of 65 standing AP pelvis radiographs. Participants were asked to score each radiograph as (1) anterior pelvic tilt more than 10 degrees, (2) posterior pelvic tilt more than 10 degrees, or (3) neutral. Responses were then compared with measurements of pelvic tilt made on lateral standing pelvic radiographs. Demographic data, such as country of practice, surgical volume, surgical approach, familiarity with spinopelvic mobility, and planning with spinopelvic mobility were evaluated. Categorical variables were compared using chi-squared analysis and analysis of variance. Continuous variables were assessed using unpaired, two-tailed Student's t-tests. A total of 45 surgeons completed the survey. The average correct predictive value of pelvic tilt between all surgeons was 53.2%. Of the responding surgeons, 51.2% performed greater than 100 cases per year. Fifty percent of surgeons reported that they were “not so familiar” or “somewhat familiar” with the principles of spinopelvic mobility. Also, 43.5% of surgeons reported that they did not routinely use spinopelvic mobility principles in THA planning. Pelvic orientation before THA is poorly predicted in our cohort of surveyed fellowship-trained AR surgeons with standing AP pelvis radiographs alone. Given the limited understanding of these principles within our cohort, preoperative evaluation of spinopelvic parameters with AP radiographs may require supplementation with lateral pelvic views to ensure detailed assessment and accurate preoperative planning. This is a prospective survey study and reflects level of evidence II.