BACKGROUND: Total hip arthroplasty (THA) frequently causes postoperative pain, hindering recovery and prolonging hospital stays. While multimodal analgesia aims to minimize opioid use and enhance outcomes, the optimal regional anesthesia technique is unclear due to the hip's complex innervation. OBJECTIVE: This multicenter randomized placebo-controlled trial evaluated whether adding an anterior quadratus lumborum block (QLB) to multimodal analgesia with non-steroidal anti-inflammatory drugs (NSAIDs) reduces opioid consumption in THA patients. METHODS: 60 adults undergoing primary unilateral THA were randomized to receive either anterior QLB with 20 mL of 0.2% ropivacaine (n = 30) or a placebo saline injection (n = 30). All participants received multimodal analgesia including NSAIDs. The primary outcome was cumulative opioid consumption in oral morphine equivalents (OMEs) within the first 24 postoperative hours. Secondary outcomes included patient experience assessed by the EVAN scale on postoperative day 1, elevated pain and opioid consumption on days 1 and 2, time to first standing, walking distance and quadriceps strength on day 1, as well as walking progression, return to sport activity and analgesic use at 3 months. RESULTS: No significant difference was found in 24-hour cumulative OME consumption between groups (median 40 mg (IQR 20-50 mg) vs 31 mg (IQR 20-45 mg)
p = 0.6). Patient experience, pain scores and opioid consumption were similar. Rehabilitation outcomes at 3 months also did not differ. CONCLUSION: Adding anterior QLB to multimodal analgesia did not reduce opioid consumption or enhance postoperative pain control and functional recovery in THA patients. Anterior QLB may not provide additional benefits when combined with multimodal analgesia with NSAID for THA. TRIAL REGISTRATION NUMBER: NCT04555291.