Comparison of continuous transmuscular quadratus lumborum block and continuous psoas compartment block for posterior total hip arthroplasty: A randomised controlled trial.

Abstract

Analgesia for hip surgery involves cutaneous anaesthesia at the site of the skin incision and the anterior hip capsule. This study aimed to compare continuous ultrasound (US)-guided transmuscular quadratus lumborum block (TQLB) with psoas compartment block (PCB) for analgesia in patients undergoing total hip arthroplasty (THA) under general anaesthesia (GA). This randomised, observer-blinded trial included 18-70-year-old American Society of Anesthesiologists physical status I-III patients undergoing THA under GA with either US-guided continuous TQLB or PCB. Primary objectives included a visual analogue scale (VAS; 0-100 mm) at rest and mobilisation at 6 h postoperatively (analysed by intention to treat and per protocol) using a non-inferiority margin of 20 mm. Secondary objectives included VAS at other time points, 24-h fentanyl consumption (analysed using the Wilcoxon rank-sum test), sensory dermatomes anaesthetised, motor weakness 30 min after block, and haemodynamic response to skin incision (analysed using the Chi-squared or Fisher's exact test). A P value less than 0.05 was considered statistically significant. VAS (0-100 mm) score at 6 h on rest was 25.34 ± 14.25 and 27.3 ± 9.6, mean difference (MD) was 1.9 [-3.3, 7.1] and at movement was 35.1 ± 23.0 and 38.6 ± 17.0, MD was 3.5 [-5.2, 12.2], in the PCB (n = 29) and QLB (n = 30) groups, respectively (i.e. less than the non-inferiority margin). However, VAS (rest) at 1, 12, and 24 h postoperatively and median (IQR) 24-h fentanyl consumption was significantly higher in the QLB group (1212.5 [300-2345] μg] when compared to the PCB group (635 [100-1645] μg; P = 0.0004). Though statistically, continuous QLB was non-inferior to continuous PCB for pain at rest and mobilisation at 6-hours postoperatively, a higher 24-hour perioperative fentanyl consumption and VAS show that QLB was clinically inferior to PCB.