Perineural dexamethasone effectively prolongs anaesthesic block duration in total hip arthroplasty, reduces opioid consumption, and does not compromise motor function, nerve integrity, or glycaemic control.

Background: Adequate postoperative analgesia is critical for elderly patients undergoing total hip arthroplasty (THA). The pericapsular nerve group (PENG) block relieves pain while preserving motor function, but its limited duration necessitates adjuncts. This study evaluates the efficacy of perineural dexamethasone in prolonging PENG block analgesia in geriatric THA patients.

Methods: In this double-blinded, randomized controlled trial, 60 patients (≥ 65 years) undergoing THA under spinal anaesthesia were assigned to the PENG group - PENG block with 20 mL 0.2% ropivacaine and the PENG + DEX group - PENG block with 20 mL 0.2% ropivacaine + 4 mg perineural dexamethasone. The primary outcome was time to first rescue opioid administration. The secondary outcomes included total opioid consumption, pain scores (NRS), quadriceps strength, and adverse effects over 48 h.

Results: Dexamethasone significantly prolonged analgesia (16.0 ± 1.3 vs. 9.0 ± 1.7 h, p < 0.0001) and reduced opioid use (0.9 ± 1.2 vs. 2.1 ± 1.4 mEQ, p = 0.0003). Pain scores were lower at six, 12, and 24 h (p < 0.05). Quadriceps strength remained intact in both groups. No nerve injuries were observed (p > 0.9999). Blood glucose levels at 12, 24, and 48 h showed no significant differences between groups (p > 0.05).

Conclusions: Perineural dexamethasone effectively prolongs PENG block duration, reduces opioid consumption, and does not compromise motor function, nerve integrity, or glycaemic control. It is a promising strategy for optimizing pain control in elderly THA patients.