Regional anesthesia strategy does not influence postoperative opioid consumption after anterior total hip arthroplasty: a large retrospective cohort study

Background Regional anesthesia is widely used to improve analgesia after total hip arthroplasty (THA). However, in contemporary anterior THA performed within standardized multimodal analgesic pathways, the impact of specific regional anesthesia strategies on postoperative opioid consumption remains uncertain. Methods We conducted a retrospective cohort study in a single high-volume orthopedic center including consecutive patients undergoing elective anterior primary THA between November 1, 2024, and April 30, 2025. Of 464 patients screened, 354 receiving general anesthesia were included in the primary analysis. Patients were allocated to four anesthetic strategies: general anesthesia (GA) alone (n = 18), GA combined with femoral nerve block (FNB; n = 62), suprainguinal fascia iliaca block (SIFIB; n = 91), or lumbar plexus block (LPB; n = 183). All blocks were ultrasound-guided. The primary outcome was cumulative oral morphine equivalents (OME) during the first 24 postoperative hours. Analysis of covariance adjusted for age, sex, body mass index, ASA physical status, intraoperative sufentanil dose, and duration of surgery. Secondary outcomes included post-anesthesia care unit (PACU) opioid consumption, PACU length of stay, and postoperative pain scores. Results After adjustment, cumulative opioid consumption during the first 24 hours did not differ significantly between anesthetic strategies (overall adjusted p = 0.439). Adjusted marginal means showed overlapping confidence intervals across groups. In contrast, PACU opioid consumption differed significantly between strategies (p < 0.001), as did PACU length of stay (p = 0.002), with higher opioid requirements and longer stays observed in patients receiving femoral nerve block. Postoperative pain scores in PACU and during the first 24 hours were similar across groups. Conclusions In patients undergoing anterior THA under general anesthesia within a contemporary multimodal analgesic framework, regional anesthesia strategy was not associated with differences in cumulative opioid consumption during the first 24 hours. However, anesthetic strategy influenced early postoperative recovery, highlighting the importance of considering PACU outcomes when selecting regional anesthesia techniques.