Introduction: The quadratus lumborum block (QLB) and the pericapsular nerve group (PENG) block both provide effective postoperative analgesia after hip surgery while minimizing impact on motor function. This study aimed to compare QLB and PENG in patients undergoing primary total hip arthroplasty. Methods: This superiority trial randomized patients scheduled for elective total hip arthroplasty to receive a lateral QLB or PENG with lateral femoral cutaneous nerve blocks for postoperative analgesia. Perioperative analgesic protocols were standardized. The primary outcome was postoperative cumulative opioid consumption at 72 hours. Secondary outcome was postoperative pain scores. Additional outcomes of interest included time to first ambulation, length of stay, patient reported outcome measures, and opioid- related side effects. Results: This trial consented and randomized 106 subjects and 101 were included in analysis: PENG (n=50), QLB (n=51). Mean (95% CI) opioid consumption (IV MME) in the first 72 hours did not differ between PENG [109.6 (93.6, 125.6)] and QL [92.3 (76.6, 107.9)] groups (p=0.129) There were no significant differences between treatment arms in average pain score, time to ambulation, distance ambulated, rate of same day discharge, or hospital length of stay. There were also no differences in patient reported outcomes using HOOS-JR and PROMIS-10 scores. Conclusion: Patients undergoing primary THA receiving preoperative PENG vs QLB had similar opioid consumption, pain scores, time to ambulation, and hospital length of stay. Both QL and PENG blocks are analgesic options in patients undergoing primary THA.

The authors have declared no competing interest.

NCT05710107

This work was supported by internal departmental support (Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina). This project was also supported by the South Carolina Clinical & Translational Research Institute, Medical University of South Carolina CTSA, NIH/NCRR Grant Number 1UL1TR001450. The contents are solely the responsibility of the authors and do not necessarily represent the official views of the NIH or NCRR.

I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained.

Yes

The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

IRB of Medical University of South Carolina gave ethical approval for this work. IRB Protocol ID: Pro00124880

I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals.

Yes

I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance).

Yes

I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable.

Yes

All data produced in the present work are contained in the manuscript