EP1.9 The literature remains heterogeneous in defining the ideal postoperative anatomy in patients with hip dysplasia undergoing periacetabular osteotomy: A systematic review and meta-analysis

Abstract Purpose Periacetabular osteotomy (PAO) is an established surgical method for treating DDH, BHD, and other acetabular deformities. Although tools for guided reorientation are increasingly available, current literature does not specify the ideal target morphology after PAO associated with substantial clinical benefit (SCB). Methods A literature review on PubMed/MEDLINE®, Embase®, and Cochrane® identified studies reporting on radiographic parameters and PROMs after PAO for DDH and BHD. Studies were excluded if previous surgeries or concomitant procedures were >25%. The review included 29 cohorts from 27 studies with 27 on DDH (2,728 hips, 2,514 patients; 97.4%) and 2 on BHD (74 hips, 71 patients; 2.6%). Study design and MINROS, patient demographics, radiographic findings, PROMs, and complications were assessed. A mixed-effect meta-analysis regression was performed, using the mean Δ (m)HHS as the effect size, weighted by the reciprocal of its variance. Different meta-regression models were used, including an anatomical and a mixed model. Covariates in the anatomical model were the mean postoperative lateral center-edge angle (LCEA) and acetabular index (AI), while the mixed-models included age and the proportion of females, combined with either the mean postoperative lateral center-edge angle (LCEA) or the acetabular index (AI). The optimal clinical goal to achieve after PAO was defined as the substantial clinical benefit (SCB) for (m)HHS >23.0 points. Results Across all DDH studies, for patients who reached the (m)HHS SCB threshold of 23.0 points, the average postoperative LCEA was 29.2° ± 5.2, and the average AI was 7.0° ± 3.8. In contrast, patients who did not achieve the SCB had a mean LCEA of 33.0° ± 5.3 and a mean AI of 6.4° ± 3.5 (p > 0.05). As only one BHD study was eligible for further analysis, only DDH studies were included in the meta-analysis regression. Neither the anatomical model nor the mixed models showed a significant association with the change in (m)HHS. Discussion The current literature shows no significant association between postoperative acetabular anatomy, patient characteristics, and the achievement of SCB. In general, comparability of the studies was limited due to heterogeneity in reporting and methods.