PENG Block and Delirium After Hip Arthroplasty

Postoperative delirium is a common and serious complication in older adults undergoing total hip arthroplasty, associated with prolonged hospitalization, increased morbidity, delayed rehabilitation, and long-term cognitive decline. Modifiable perioperative risk factors include uncontrolled postoperative pain, opioid consumption, impaired early mobilization, and systemic inflammatory response. The Pericapsular Nerve Group (PENG) block is a regional anesthesia technique targeting the sensory innervation of the anterior hip capsule and may provide effective analgesia while preserving motor function. Improved pain control and opioid reduction may decrease the incidence of postoperative delirium. This prospective, randomized, parallel-group controlled trial aims to evaluate whether the addition of ultrasound-guided PENG block to spinal anesthesia reduces the incidence of postoperative delirium within 72 hours after primary total hip arthroplasty in patients aged 65 years or older. Delirium will be assessed using the Confusion Assessment Method (CAM) by blinded outcome assessors. Secondary outcomes include postoperative opioid consumption, pain intensity (NRS), time to first rescue opioid, postoperative nausea and vomiting, time to mobilization, block-related adverse events, and perioperative inflammatory indices (neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio). The study will enroll 144 patients randomized 1:1 to spinal anesthesia alone or spinal anesthesia plus PENG block.