Background: Periacetabular Osteotomy (PAO) is a well-established procedure, however more prospective cohort studies are required to assess all clinical factors related to this invasive intervention. The aims of this study are as follows 1) quantifying stress fractures, delayed-healing and non-union post PAO and 2) to correlate possible risk factors for developing symptomatic stress fracture, delayed-healing or non-union.

Methods: We retrospectively collected radiologic and baseline data of the patient cohort and prospectively evaluated radiologic images for stress fractures, delayed-healing and non-union. A total of 621 hips (537 patients with a mean age 31.8, ranging 18 to 58 years) between January 2004 and December 2017 were included of which females composed the majority (78%). Compiled data were analyzed by utilizing chi-square and t-test for stress fracture, delayed-healing and non-union for risk factor determination.

Results: In this cohort comprising 621 hips, this study determined the prevalence rates of stress fractures, delayed healing, and non-union following PAO surgery to be 4.0%, 2.3%, and 5.6%, respectively. A detailed analysis of the data pertaining to patients who experienced stress fractures revealed three significant variables associated with their occurrence: higher body mass index (BMI), lower Wiberg’s Center Edge (CE) angle, and higher AA angle. Furthermore, the incidence of delayed healing was also significantly related to higher BMI, lower CE angle, and higher Acetabular Index (AA) angle. While the risk of non-union was found to be significantly associated with both higher BMI and a history of smoking.

Conclusions: This study has quantified the prevalence of stress fracture, delayed-healing and non-union for patients that have undergone PAO and suggested an increased risk of aforementioned adverse events for certain baseline values.

Periacetabular osteotomy, Pelvic stress fracture, Hip dysplasia, Risk factor