Pelvic tilt remains unchanged after periacetabular osteotomy: A single‐arm multilevel meta‐analysis and meta‐regression

Abstract Purpose Understanding changes in pelvic tilt (PT) after periacetabular osteotomy (PAO) is essential for surgical planning and outcome assessment. This study aimed to synthesise current evidence on pre‐ and postoperative PT and identify associated factors using meta‐regression. Methods A systematic search of PubMed, Embase, and Epistemonikos was conducted through 31 May 2025. A single‐arm multilevel meta‐analysis was performed using a random‐effects model to estimate mean PT values before and after PAO. Subgroup analyses examined differences based on surgical indication (DDH/BDDH vs. others) and unilateral vs. bilateral surgery. Meta‐regression assessed the impact of age, sex and BMI on PT outcomes. Statistical analyses were performed using R. Results Twelve primary studies comprising 680 patients (785 hips) were included. The mean preoperative pelvic tilt (PT) was 8.13° and decreased slightly postoperatively to 6.81°, with no statistically significant overall change. The greatest positional change was observed in the sitting position (mean difference: 12.01°), though this was also not statistically significant. Subgroup analyses showed no significant differences in PT based on operative indication or unilateral vs. bilateral surgery. Meta‐regression identified patient age as a significant predictor of postoperative PT in the sitting position ( β = –4.45, 95% CI: –8.48 to –0.41; p = 0.0454), with older age associated with lower PT values. No significant associations were found for sex or BMI. Conclusion Pelvic tilt remains largely unchanged after PAO, regardless of operative indication or surgical laterality. However, older age is associated with lower postoperative PT in the sitting position, highlighting the importance of considering individual patient characteristics in surgical planning and assessment. Level of Evidence Level IIa, systematic review and meta‐analysis of predominantly prospective and retrospective cohort studies.