Iliopsoas plane block does not improve pain after primary total hip arthroplasty in the presence of multimodal analgesia: a single institution randomized controlled trial

Background The clinical analgesic efficacy of iliopsoas plane block remains a subject of discussion. This study aimed to assess the analgesic efficacy of iliopsoas plane block under general anesthesia using multimodal analgesia. Methods Fifty-six adult patients who underwent elective primary hip arthroplasty were enrolled. Patients were randomized to receive either a single-shot iliopsoas plane block (10 mL 0.75% ropivacaine with 1:200 000 epinephrine) or a sham block (10 mL normal saline). All patients received general anesthesia, multimodal analgesia (preoperative buprenorphine patch, 5 µg/h), intraoperative intravenous dexamethasone (8 mg) and nefopam (20 mg), and round-the-clock acetaminophen and celecoxib. The primary outcome was the numeric rating scale pain score at rest 6 hour after surgery. Results Iliopsoas plane block did not have a notable advantage over the sham block in terms of pain relief at rest, as assessed by the numeric rating scale score, 6 hour after total hip arthroplasty (iliopsoas plane block: median, 4.0; IQR, 2.0–5.8; sham: median, 5.5; IQR, 2.3–6.8; median difference, −1.0; 95% CI −2.0 to 0.0; p≥0.999). Linear mixed model analysis showed no differences in pain scores, opioid consumption, quadriceps strength, or quality of recovery between the groups. Conclusions Iliopsoas plane block did not improve postoperative analgesia following total hip arthroplasty under general anesthesia with a multimodal analgesic regimen. The blockade of sensory femoral branches supplying the anterior hip capsule using iliopsoas plane block may not yield additional benefits concerning patient outcomes in the aforementioned clinical context. Trial registration number NCT05212038 , https://clinicaltrials.gov/ct2/show/NCT05212038