Effect of bupivacaine concentration on ultrasound-guided pericapsular group nerve block efficacy in hip surgery patients: comparative, randomized, double-blinded clinical trial

The pericapsular nerve group (PENG) block offers effective postoperative pain relief following hip fracture surgery. This research investigated three doses of bupivacaine, all administered in the same total volume, for performing ultrasound-guided PENG blocks during hip fracture procedures. This randomized, double-blinded clinical trial was conducted on 135 patients aged between 18 and 70 years of both sexes who underwent hip fracture surgeries. Participants were randomized into three groups ( n = 45). Ultrasound-guided PENG block was applied, the groups received 20 mL of local anesthetics. The first group received 0.5% bupivacaine, the second group received 0.375% bupivacaine, and the third group received 0.25% bupivacaine. The following parameters were recorded: onset of sensory block, resting NRS after passively raising the limb by 15° half an hour post-procedure, quality of recovery score (QoR-15) at 24 h postoperative. The 0.25% bupivacaine group exhibited a longer sensory block onset than the other groups ( p ≤ .05). Significant differences were demonstrated between the groups regarding the time to 1st analgesia ( p = .033) and total morphine consumption ( p = .025). NRS at baseline and T30 post-block did not show significant differences between the studied groups. No significant differences were detected postoperatively in rest and dynamic NRS ( p ≤ .05). Patient satisfaction, QoR-15 score, and ease of spinal positioning did not differ between the groups. Compared to 0.25% bupivacaine, PENG block with 0.5% and 0.375% bupivacaine provided a rapid onset sensory block, delayed first analgesic requirements, and reduced total morphine consumption after hip surgeries. The trial was registered at the clinicaltrials.gov with study number (Trial ID: NCT05788458).