Efficacy of iliopsoas plane block for patients undergoing hip arthroscopy: a prospective, triple-blind, randomized, placebo-controlled trial

Background: Intraoperative stretching of the hip joint capsule often generates severe pain during the first 3 hours after hip arthroscopy. The short-lived severe pain mandates high opioid consumption, which may result in adverse events and delay recovery. The femoral nerve nociceptors are located anteriorly in the hip joint capsule. A femoral nerve block reduces pain and opioid demand after hip arthroscopy. It impedes, however, ambulation and home discharge after outpatient surgery. The iliopsoas plane block selectively anesthetizes the femoral sensory nerve branches innervating the hip joint capsule without compromising ambulation. We aimed to assess reduction of opioid consumption after iliopsoas plane block during the short-lived painful postsurgical period of time after hip arthroscopy. Methods: In a randomized, triple-blind trial, 50 patients scheduled for hip arthroscopy in general anesthesia were allocated to active or placebo iliopsoas plane block. The primary outcome was opioid consumption during the first three postoperative hours in the postanesthesia care unit. Secondary outcomes included pain, nausea, and ability to ambulate. Results: Forty-nine patients were analyzed for the primary outcome. The mean 3-hour intravenous morphine equivalent consumption in the iliopsoas plane block group was 10.4 mg vs 23.8 mg in the placebo group (p<0.001). No intergroup differences were observed for the secondary outcomes during the postoperative follow-up. Conclusion: An iliopsoas plane block reduces opioid consumption after hip arthroscopy. The reduction of opioid consumption during the clinically relevant 3-hour postsurgical period of time was larger than 50% for active versus placebo iliopsoas plane block in this randomized, triple-blind trial.