Comparison between the ultrasound guided pericapsular nerve group block and anterior quadratus lumborum block in elderly patients undergoing total hip replacement surgeries: a randomized controlled clinical trial.

Background: To compare the safety and efficacy of ultrasound-guided pericapsular nerve group (PENG) block and anterior quadratus lumborum block (AQLB) in elderly patients undergoing total hip arthroplasty (THA).

Methods: This randomized, controlled trial included 93 patients aged 65 years or older with traumatic hip fractures, scheduled for elective unilateral THA under general anesthesia. Patients were randomized into three groups: PENG group (N.=31), AQLB group (N.=31), and a control group (N.=31), which received only opioid analgesia. The primary outcome was total morphine consumption within the first 24 hours postoperatively. Secondary outcomes included intraoperative fentanyl use, time to first rescue analgesia, block failure rate, pain scores at rest and during movement, motor recovery (muscle strength and hip flexion), time to first ambulation, and length of hospital stay. Additional assessments involved intraoperative hemodynamic monitoring, block-related and morphine-related complications, as well as block performance time and duration of surgery.

Results: The AQLB group showed the least total morphine consumption (median 6.0 mg), followed by the PENG group (median 8.0 mg), with a significant difference between the two groups (P=0.035). Both PENG and AQLB groups showed a significantly lower total morphine consumption than the control group (median=12.0 mg). The Numeric Pain Rating Scale at rest showed significant differences between "AQLB versus Control" till 4 hours postoperative, and between "PENG versus Control" at all-time points except at 6, 8, and 18 hours. The AQLB group showed the lowest scores for the manual muscle test for the quadriceps and Iliopsoas muscles and for the range of motion with significant differences between AQLB and PENG. Furthermore, the time to first walk was significantly longer among the AQLB group (median 24 h) in comparison to the PENG group (median 8 h). The PENG displayed the shortest hospital stay period (2.13 days), followed by the control group (2.94 days), and then the AQLB group (3.16 days), with significant differences.

Conclusions: While the PENG block facilitated earlier mobilization and shorter hospital stays, the AQLB offered superior analgesia and reduced opioid consumption. Both techniques proved effective, with the choice depending on clinical priorities such as pain control versus early recovery.