High incidence of acetabular retroversion in gluteal muscle contracture patients based on X-ray film

Objective: In the clinic, gluteus muscle contracture (GMC) is found to cause pelvic structural changes, including acetabular retroversion (AR). However, its incidence has not been reported. This study aimed to explore the anteroposterior pelvic radiographs of GMC patients to identify the prevalence of AR. Methods The imaging characteristics of anteroposterior pelvic radiographs on 100 cases of GMC and 100 healthy people were analyzed. GMC was diagnosed by ‘iliac hyperdense line’(IHDL), while ‘prominence of the ischial spine’ (PRIS) or cross-over sign’ (COS) were used to define AR. Results ‘iliac hyperdense line’ was only observed in GMC patients (92%). There were 80 cases that showed PRIS in the GMC group, but only 19 in the control group. Similarly, the incidence of COS was 76% in patients and 5% in normal people. All the differences between the two groups of these indicators were statistically significant (P < 0.001). Furthermore, a statistical correlation was confirmed between PRIS and COS when they were positive in GMC patients. Conclusion AR showed a high incidence in patients with GMC based on PRIS and COS.