Background

Positioning patients with painful hip fractures for spinal anaesthesia can be challenging. Femoral nerve block (FNB) provides analgesia but may incompletely cover hip capsular innervation and cause quadriceps weakness. The pericapsular nerve group (PENG) block may provide more comprehensive, motor-sparing analgesia. This study compared the analgesic efficacy of PENG block and FNB before spinal anaesthesia for hip surgery.

Methods

This prospective, randomized, assessor-blinded trial included 76 adults undergoing hip surgery under spinal anaesthesia. Participants were allocated equally to receive ultrasound-guided PENG block or FNB using 20 mL of 0.25% bupivacaine. Dynamic numerical rating scale (NRS) scores were recorded at baseline and 10, 20 and 30 minutes after block administration. The primary outcome was reduction in dynamic NRS at 30 minutes. Secondary outcomes included positioning pain and quality, spinal attempts, rescue fentanyl, postoperative analgesia, quadriceps weakness, ambulation and adverse events.

Results

Baseline characteristics were comparable between the groups. At 30 minutes, dynamic NRS was lower with PENG block than FNB (2.2±1.1 versus 3.8±1.4; p<0.001), with a greater reduction from baseline (6.1±1.2 versus 4.4±1.5; p<0.001). PENG block reduced positioning pain (2.5±1.2 versus 4.1±1.5; p<0.001) and positioning time (2.6±0.8 versus 3.8±1.1 minutes; p<0.001). Optimal positioning was more frequent (73.7% versus 44.7%; p=0.019), whereas rescue fentanyl use was lower (7.9% versus 31.6%; p=0.019). Time to first rescue analgesia was prolonged (8.9±2.6 versus 6.4±2.1 hours; p<0.001), and 24-hour tramadol consumption was reduced (71.1±45.8 versus 110.5±52.6 mg; p=0.001). Quadriceps weakness at 30 minutes occurred in 10.5% versus 42.1% of patients (p=0.004). Adverse events were comparable.

Conclusion

PENG block provided superior pre-spinal and postoperative analgesia, improved positioning conditions and better preserved quadriceps strength compared with FNB, without increasing complications.