Posterior Quadratus Lumborum Block in Total Hip Arthroplasty: A Randomized Controlled Trial

Background: Pain management is important for ensuring early mobilization after hip arthroplasty; however, the optimal components remain controversial. Recently, the quadratus lumborum block has been proposed as an analgesic option. The current study tested the hypothesis that the posterior quadratus lumborum block combined with multimodal analgesia decreases morphine consumption after hip arthroplasty. Methods: This study was a prospective, randomized, double-blind, placebo-controlled trial. Before general anesthesia, 100 participating patients scheduled for elective total hip arthroplasty were randomly allocated to receive a 30-ml injection posterior to the quadratus lumborum muscle with either 0.33% ropivacaine (n = 50) or normal saline (n = 50). For all patients, multimodal analgesia included systematic administration of acetaminophen, ketoprofen, and a morphine intravenous patient-controlled analgesia. The primary outcome was total intravenous morphine consumption in the first 24 h. Secondary outcomes recorded intraoperative sufentanil consumption; morphine consumption in the postanesthesia care unit; pain scores at extubation and at 2, 6, 12, and 24 h; motor blockade; time to first standing and ambulation; hospital length of stay; and adverse events. Results: There was no significant difference in the 24-h total morphine consumption (ropivacaine group, median [interquartile range], 13 [7 to 21] versus saline group, 16 [9 to 21] mg; median difference, -1.5; 95% CI, -5 to 2; P = 0.337). Pain scores were not different between the groups (beta = -0.4; 95% CI, -0.9 to 0.2; P = 0.199). There was no statistical difference between the two groups in intraoperative sufentanil consumption, morphine consumption in the postanesthesia care unit, motor blockade, times to first standing (median difference, 0.83 h; 95% CI, -1.7 to 3.4; P = 0.690) and ambulation (median difference, -1.85 h; 95% CI, -4.5 to 0.8; P = 0.173), hospital length of stay, and adverse events. Conclusions: After elective hip arthroplasty, neither morphine consumption nor pain scores were reduced by the addition of a posterior quadratus lumborum block to a multimodal analgesia regimen.