An Obturator Nerve Block does not Alleviate Postoperative Pain after Total Hip Arthroplasty: a Randomized Clinical Trial

Abstract

Background and objectivesA 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.MethodsSixty-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.ResultsSixty 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.ConclusionsA significant reduction in postoperative opioid consumption was not found for active versus PCB ONB after THA.Trial registration number NCT03064165 and 2017-000068-14.

Ultrasound-guided supra-inguinal fascia Iliaca compartment block for older adults admitted to the emergency department with hip fracture: a randomized controlled, double-blind clinical trial

“…There was no difference in the resting VAS between the two groups, and our explanations for this follow. 1) The obturator nerve plays a limited role at rest, with a study showing that the block of the obturator nerve did not relieve pain after total hip arthroplasty [23]; this suggests that the obturator nerve was less important than the femoral nerve in analgesia during hip fractures. 2) There might be errors in the assessment of the obturator nerve block, as accurate assessments have proven quite difficult due to significant variation in the cutaneous distribution of the obturator nerve.…”

The Effect of the Minimum Effective Volume for Suprainguinal Fascia Iliaca Block in Fresh Cadavers

“…The efficiency of the SFIB with ON block, on the other hand, is still debatable. In some previous studies, the ON block did not reduce pain after hip arthroplasty (Nielsen et al, 2019). At present, Zheng et al (2021) improved the USG-SFIB technique of analgesic for total hip arthroplasty.…”

Peripheral nerve blocks for analgesia after elective total hip arthroplasty

“…Study II revealed that an ONB had no effect on post‐operative pain after THA; subjects with an ONB had an opioid consumption of (mean [SD]) 39.9 [22.3] mg opioids (oral morphine equivalents) during the first 12 post‐operative hours. The corresponding dose in controls was 40.5 [30.5] mg ( P = .93) . In Study III, we found that an IPB did not induce muscle weakness in volunteers.…”