Methods

We performed a retrospective cohort study on all patients (n=223, n=274 hips) who underwent a PAO procedure between May 1996 and May 2016, by a single surgeon at one academic center. Cases with a history of retroversion (n=64), Perthes (n=5), and those with <2 years of follow-up (n=63) were excluded. Patients were evaluated based on severity of dysplasia using the preoperative lateral center edge angle (LCEA): 18° – 25° was considered mild dysplasia (n=19), 10° – 17° moderate (n=62), and <10° severe (n=61). There was no difference in patient characteristics (age, sex, body mass index, or ASA score) between then cohorts (all, p>0.05). NIH PROMIS outcome measures included the physical function computerized adaptive test (PF CAT) and the Global 10 health assessment. Generalized estimating equations were used for all comparisons and missing data was imputed using the multivariate imputation by chained equations method. A Kaplan-Meier analysis was used to assess survival. Failure was defined as conversion to THA and follow-up was ended at time of failure or at the time of last follow-up. Mean follow-up was five years (1 – 19).