RT Journal Article SR Electronic T1 An Obturator Nerve Block does not Alleviate Postoperative Pain after Total Hip Arthroplasty: a Randomized Clinical Trial JF Regional Anesthesia & Pain Medicine JO Reg Anesth Pain Med FD BMJ Publishing Group Ltd SP 466 OP 471 DO 10.1136/rapm-2018-100104 VO 44 IS 4 A1 Niels Dalsgaard Nielsen A1 Charlotte Runge A1 Louise Clemmesen A1 Jens Børglum A1 Lone Ramer Mikkelsen A1 Jens Rolighed Larsen A1 Thomas Dahl Nielsen A1 Kjeld Søballe A1 Thomas Fichtner Bendtsen YR 2019 UL http://rapm.bmj.com/content/44/4/466.abstract AB Background and objectives A substantial group of patients suffer from moderate to severe pain following elective total hip arthroplasty (THA). Due to the complex innervation of the hip, peripheral nerve block techniques can be challenging and are not widely used. Since the obturator nerve innervates both the anteromedial part of the joint capsule as well as intra-articular nociceptors, we hypothesized that an obturator nerve block (ONB) would decrease the opioid consumption after THA.Methods Sixty-two patients were randomized to receive ONB or placebo (PCB) after primary THA in spinal anesthesia. Primary outcome measure was opioid consumption during the first 12 postoperative hours. Secondary outcome measures included postoperative pain score, nausea score and ability to ambulate.Results Sixty patients were included in the analysis. Mean (SD) opioid consumption during the first 12 postoperative hours was 39.9 (22.3) mg peroral morphine equivalents (PME) in the ONB group and 40.5 (30.5) mg PME in the PCB group (p=0.93). No difference in level of pain or nausea was found between the groups. Paralysis of the hip adductor muscles in the ONB group reduced the control of the operated lower extremity compared with the PCB group (p=0.026). This did, however, not affect the subjects’ ability to ambulate.Conclusions A significant reduction in postoperative opioid consumption was not found for active versus PCB ONB after THA.Trial registration number NCT03064165 and 2017-000068-14.