Substantial blood loss and transfusion burden after periacetabular osteotomy: Benchmark estimates from a systematic review and meta‐analysis

PURPOSE: To establish pooled benchmark estimates for perioperative blood loss and transfusion burden after periacetabular osteotomy (PAO) and to explore potential study-level moderators across the available literature. METHODS: A systematic search of PubMed, Embase, Epistemonikos and CENTRAL was performed up to 30 March 2026. Prospective and retrospective primary clinical studies reporting at least one predefined perioperative blood management outcome after PAO were included. Outcomes comprised transfusion rate, units transfused, intraoperative blood loss, estimated blood loss, haemoglobin drop and postoperative haemoglobin levels. Random-effects meta-analyses of proportions and means were performed. Univariable meta-regression was used to explore study-level moderators. RESULTS: Forty-seven studies comprising 4402 patients and 4767 hips were included. The pooled transfusion rate was 16.2% (95% confidence interval [CI] = 11.1-23.0), and the pooled mean number of transfused units was 1.94 (95% CI = 1.32-2.55). The pooled mean intraoperative blood loss was 961.8 mL (95% CI = 804.1-1119.5), and the pooled mean estimated blood loss was 809.9 mL (95% CI = 706.4-913.5). The pooled mean haemoglobin drop was 32.4 g/L (95% CI = 27.7-37.1), and the pooled mean postoperative haemoglobin level was 99.4 g/L (95% CI = 97.2-101.6). Longer operative time was significantly associated with higher intraoperative and estimated blood loss. Higher preoperative haemoglobin was associated with greater haemoglobin drop, while higher age was associated with transfusion-related outcomes. CONCLUSION: PAO is associated with substantial perioperative blood loss and a relevant transfusion burden. These pooled estimates provide clinically useful benchmark values for perioperative blood management after PAO. LEVEL OF EVIDENCE: Level III systematic review and meta-analysis of predominantly retrospective cohort studies.