PENG Block vs Suprainguinal FICB vs Lumbar ESPB for Analgesia After Hip Surgery

Regional anesthesia plays a key role in modern multimodal analgesia for hip arthroplasty, particularly in older adults who are vulnerable to opioid-related adverse effects and postoperative functional decline. Several motor-sparing nerve block techniques have been developed to improve postoperative pain control while maintaining quadriceps strength and enabling early mobilization. Among them, the Pericapsular Nerve Group (PENG) block, the suprainguinal Fascia Iliaca Compartment Block (S-FICB), and the Lumbar Erector Spinae Plane Block (L-ESPB) are widely used in clinical practice. However, no randomized clinical trial has directly compared these three approaches within a single study population. The PENG block targets the articular branches of the femoral, obturator, and accessory obturator nerves, providing selective analgesia of the anterior hip capsule with minimal motor involvement. The suprainguinal FICB delivers a higher spread of local anesthetic over the femoral nerve, lateral femoral cutaneous nerve, and variable portions of the obturator nerve, offering broader sensory coverage but with a higher likelihood of quadriceps weakness. The lumbar ESPB is a posterior fascial plane block that may achieve indirect spread toward the lumbar plexus, potentially providing balanced anterior and posterior capsular analgesia while preserving motor function. This randomized, double-blinded, three-arm controlled trial aims to compare the analgesic effectiveness, opioid-sparing properties, and motor-sparing characteristics of PENG, S-FICB, and L-ESPB in patients undergoing hip arthroplasty. All participants will receive standardized spinal anesthesia and multimodal postoperative analgesia. The study's primary endpoint is the time to first rescue opioid administration. Secondary outcomes include total postoperative opioid consumption, pain scores at rest and during movement, quadriceps muscle strength, block performance time, incidence of postoperative nausea and vomiting, early mobilization parameters, and block-related adverse events. The results of this trial are expected to clarify the relative benefits and limitations of the three most commonly used motor-sparing regional anesthesia techniques for hip surgery and to guide optimal selection of blocks for enhanced recovery pathways in older adults undergoing hip arthroplasty.