The Prospective Randomized Controlled Study Comparing the Analgesic Effects and Quadriceps Strength between Femoral Nerve Block and PENG Block in Patients Undergoing Hip Fracture Surgery

Hip fracture surgery causes moderate to severe postoperative pain requiring effective analgesic management. While femoral nerve block (FNB) is commonly used for postoperative analgesia, it may compromise quadriceps strength and delay mobilization. The pericapsular nerve group (PENG) block, a novel regional technique targeting specific articular branches, is hypothesized to provide effective pain relief while preserving quadriceps function more effectively, but comparative evidence is limited. The purpose of this study was to compare the analgesic efficacy and preservation of quadriceps muscle strength between PENG block and FNB in patients undergoing hip fracture surgery. Methods: A prospective, randomized, double-blind trial was conducted with 70 patients undergoing hip fracture surgery. Participants were randomly assigned to receive either FNB or PENG block, with all patients receiving spinal anesthesia with intrathecal morphine. Primary outcomes included Tramadol consumption and time to first analgesic dose. Secondary outcomes included postoperative quadriceps strength, pain scores, and adverse effects. Median Tramadol consumption in the first 24 hr post-surgery was significantly lower in the PENG group compared to the FNB group (0 mg [IQR: 0-50] vs. 50 mg [IQR: 50-50], p = 0.002). Time to first Tramadol dose was significantly longer in the PENG group (20.87 ± 4.96 vs. 15.35 ± 6.37 hr, p < 0.001). Pain scores during 4-12 hr post-surgery were significantly lower in the PENG group (median difference 1-2 points, p < 0.05). Quadriceps strength at postoperative 24 hr was significantly better preserved in the PENG group, with 71.43% showing intact strength compared to 22.86% in the FNB group (p < 0.001). Postoperative nausea and vomiting were significantly lower in the PENG group (20% vs. 44.12%, p = 0.04). PENG block provides superior postoperative analgesia with better preservation of quadriceps strength compared to FNB in patients undergoing hip fracture surgery, when used as an adjunct to spinal anesthesia with intrathecal morphine. These benefits may facilitate earlier mobilization and enhanced recovery, though further studies are needed to assess the individual contributions of each analgesic modality.