Intraoperative hypotension and short-term outcomes after primary total hip arthroplasty : a retrospective cohort study.

Aims: Intraoperative hypotension (IOH) has been associated with adverse outcomes in non-cardiac surgery, but its effect during total hip arthroplasty (THA) remains unclear. This study aimed to investigate whether absolute (AIOH) or relative (RIOH) IOH is a risk factor for adverse short-term outcomes following primary THA. Methods: A retrospective review of 394 THAs (394 patients) performed at a single academic institution between September 2020 and April 2025 was conducted. AIOH was defined as any intraoperative mean arterial pressure (MAP) < 65 mmHg, and RIOH as a ≥ 20% decrease from preoperative baseline MAP. Primary outcomes included all-cause 30- and 90-day readmissions and postoperative length of stay (LOS). Multivariable logistic regression was used to identify predictors of readmission and LOS > one day. Results: Overall, 112 patients (28.4%) experienced AIOH during their THA. Neither the presence nor duration of AIOH was associated with readmission or LOS. RIOH occurred in 74 patients (22.5%), and was not associated with readmission or LOS, but was associated with higher rates of reoperation within 90 days (12.2% vs 2.4%, p = 0.001). Estimated blood loss independently predicted prolonged LOS across all models (odds ratio 1.75 per 50 ml, 95% CI 1.33 to 2.31, p < 0.001). Conclusion: AIOH was not associated with an increased risk of adverse short-term outcomes following primary THA when defined by a fixed MAP threshold. RIOH and intraoperative blood loss demonstrated stronger associations with postoperative complications, but these findings require further evaluation. This study supports a more individualized approach to haemodynamic monitoring in primary THA.