Efficacy and Safety of Dexmedetomidine as an Adjuvant to Bupivacaine in Ultrasound-Guided Pericapsular Nerve Group (PENG) Block for Proximal Femoral Fractures: A Randomised, Single-Centre Controlled Trial

Background: Dexmedetomidine has been used in many peripheral nerve blocks, as it enhances the duration of analgesia and hastens its onset. We compared whether adding dexmedetomidine to bupivacaine in the pericapsular nerve group (PENG) block resulted in prolonged duration of analgesia with ease of positioning for spinal anaesthesia in proximal femur fractures without adverse effects. Methods: This prospective randomised study was conducted in a tertiary care hospital in North India between January 2024 and June 2024 after institutional ethics approval and Clinical Trials Registry of India (CTRI) registration (CTRI/2024/12/078728). Sixty adult patients aged 18-60 years, with American Society of Anesthesiologists (ASA) physical status I-III, presenting with proximal femur fractures less than seven days old and moderate to severe pain (numeric rating score (NRS) > 4), scheduled for surgery, were randomly allocated to Group A or Group B. Group A received 20 mL of 0.25% bupivacaine with 50 mcg dexmedetomidine (0.5 mL) for the PENG block, while Group B received 20 mL of 0.25% bupivacaine with 0.5 mL of saline for the PENG block. The primary outcome was the duration of analgesia. Secondary outcomes included ease of spinal positioning score, postoperative pain scores, postoperative opioid requirement, quadriceps strength at 24 hours, and adverse events. Results: In this single-centre trial, the use of dexmedetomidine as a perineural adjuvant in the PENG block was associated with a prolonged duration of analgesia (95% CI: 2.89-4.71; p < 0.001), better positioning scores (p < 0.001), and lower postoperative pain scores compared to bupivacaine alone in 60 patients aged 18-60 years. Motor function was preserved in both groups, and no significant adverse events were observed. Conclusions: Dexmedetomidine is a safe and effective adjuvant for the PENG block in proximal femur fracture surgeries in adults aged 18-60 years. Further studies in geriatric populations are required for broader clinical recommendations.