Comparison of pericapsular nerve group block combined with a lateral femoral cutaneous nerve (LFCN) block versus lumbar and sacral erector spinae plane blocks for analgesia after total hip arthroplasty: study protocol for a randomized, controlled tri

INTRODUCTION: Postoperative pain after total hip arthroplasty (THA) remains a major barrier to early mobilization and recovery in older adults. Enhanced recovery pathways increasingly emphasize potentially motor-sparing regional anesthesia to ensure effective analgesia while preserving lower-limb strength and reducing opioid use. AREAS COVERED: This prospective, randomized, controlled trial with blinded outcome assessment compares two potentially motor-sparing regional analgesic strategies in elderly patients undergoing elective THA under spinal anesthesia. Patients receive either a pericapsular nerve group block combined with a lateral femoral cutaneous nerve block or a combined lumbar and sacral erector spinae plane block, with spinal anesthesia alone as the control. The primary outcome is cumulative opioid consumption during the first 48 postoperative hours, expressed as morphine milligram equivalents. Secondary outcomes include postoperative pain intensity, quadriceps strength, time to first ambulation, and adverse events. The protocol is based on recent randomized trials, systematic reviews, and anatomical studies of potentially motor-sparing techniques for hip surgery. The trial is registered at ClinicalTrials.gov (NCT07180979). EXPERT OPINION/COMMENTARY: This trial aims to compare the clinical profiles of targeted capsular versus segmental fascial plane approaches for postoperative analgesia in THA and to support evidence-based optimization of potentially motor-sparing regional anesthesia in elderly patients. CLINICAL TRIAL REGISTRATION: The www.clinicaltrials.gov identifier is NCT07180979.