Comparison of pericapsular nerve group and lateral quadratus lumborum blocks on cumulative opioid consumption after primary total hip arthroplasty: a randomized controlled trial

Introduction Both the quadratus lumborum block (QLB) and the pericapsular nerve group (PENG) block provide effective postoperative analgesia after hip surgery while minimizing the impact on motor function. This study aimed to compare QLB and PENG in patients undergoing primary total hip arthroplasty (THA). Methods This superiority trial randomized patients scheduled for elective THA to receive a lateral QLB or a PENG with a lateral femoral cutaneous nerve (LFC) block for postoperative analgesia. Perioperative analgesic protocols were standardized. The primary outcome was postoperative cumulative opioid consumption measured over time up to 72 hours. Secondary outcomes included postoperative pain scores in the first 72 hours, time to ambulation, length of stay, and patient-reported functional outcome measures (Hip disability and Osteoarthritis Outcome Score for Joint Replacement and Patient-Reported Outcome Measures Information System-10 scores). Results This trial consented and randomized 106 subjects and 101 were included in the analysis: PENG (n=50), QLB (n=51). Mean (95% CI) opioid consumption in intravenous morphine milligram equivalents differed at 36 hours (mean difference (95% CI), 18.0 (0.80, 35.1); p = 0.040), 48 hours (23.0 (5.20, 40.8); p=0.011), 60 hours (28.0 (9.24, 46.7); p=0.004), and 72 hours (33.0 (13.0, 53.0); p=0.001). There were no significant differences between treatment arms in average resting pain score, time to ambulation, rate of same-day discharge, length of stay, or patient-reported functional outcomes. Conclusion While both lateral QLB and PENG block+LFC block are effective analgesic methods for patients undergoing THA, patients receiving lateral QLB had decreased cumulative opioid consumption from 36 to 72 hours postoperative and lower pain scores with movement compared with patients receiving PENG+LFC blocks. Trial registration number NCT05710107 .