Early Functional Outcomes of Periacetabular Osteotomy After Failed Hip Arthroscopic Surgery for Symptomatic Acetabular Dysplasia

Background: Persistent acetabular dysplasia is a common reason for the failure of hip arthroscopic surgery; however, the effect of prior hip arthroscopic surgery on functional outcomes after subsequent periacetabular osteotomy (PAO) is unknown. Hypothesis/Purpose: The purpose of this study was to (1) compare demographic and radiological findings in patients who had and had not undergone previous hip arthroscopic surgery before PAO for symptomatic acetabular dysplasia and (2) compare the short-term, hip-specific patient-reported outcomes in these same patient populations. It was hypothesized that prior hip arthroscopic surgery is associated with worse early functional outcomes in PAO. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective cohort study design was utilized. Patients undergoing PAO were enrolled from a single-center, prospective hip preservation registry from March 2011 to April 2015. Patients with a minimum of 1-year clinical follow-up with preoperative and postoperative outcome scores undergoing PAO were eligible for inclusion (n = 93 patients; mean clinical follow-up, 24 months [range, 11-58 months]). The study group consisted of patients undergoing PAO for symptomatic hip dysplasia after prior hip arthroscopic surgery (PREVSCOPE group; 22 patients, 25 hips). Patients undergoing PAO without prior hip arthroscopic surgery (PAOALONE group; 71 patients, 85 hips) were included as a comparison group. Demographic and radiological variables were recorded. Postoperative functional outcome scores (modified Harris Hip Score [mHHS], Hip Outcome Score [HOS], and International Hip Outcome Tool [iHOT-33]) were recorded at 6 months and annually postoperatively. Results: There were no demographic differences between the 2 groups at baseline. Acetabular version, femoral version, Tonnis grade, preoperative lateral center edge angle, and intraoperative procedures were not different between the 2 groups. At 1-year follow-up from the last hip surgical procedure, the mean (+/- SD) mHHS (73 +/- 14 vs 86 +/- 14, respectively; P < .001), HOS-Activities of Daily Living (84 +/- 12 vs 93 +/- 11, respectively; P = .007), HOS-Sport (62 +/- 25 vs 85 +/- 18, respectively; P < .001), and iHOT-33 (62 +/- 21 vs 79 +/- 20, respectively; P = .004) were decreased in the PREVSCOPE group versus the PAOALONE group. At last follow-up (mean, 18 months from the last hip surgical procedure), the mHHS and HOS-Sport were lower in the PREVSCOPE group versus the PAOALONE group. There was no difference in complication or reoperation rates between the 2 groups. Conclusion: Failed hip arthroscopic surgery before PAO for symptomatic hip dysplasia is associated with lower hip-specific functional outcomes within the first 1 year of follow-up despite similar baseline demographic and radiological characteristics. These differences persisted in certain outcome scores (mHHS, HOS-Sport) at last follow-up but were less pronounced than at 1 year.