BACKGROUND: Closed reduction of distal radius fractures is painful, and current analgesic strategies may be inadequate. Ultrasound-guided lateral infraclavicular brachial plexus block may offer complete analgesia and muscle relaxation, potentially improving patient comfort and reduction quality. However, benefits and challenges regarding anesthetic agents for this procedure remain unclear. METHODS: In this randomized, controlled, blinded, noninferiority trial, 63 adults with distal radius fractures requiring closed reduction received a lateral infraclavicular block with either 30 mL of ropivacaine 0.5%, lidocaine 1% with epinephrine, or ropivacaine 0.2%. The primary outcome was block success at 45 min, defined as complete sensory and extensive motor block of the radial, musculocutaneous, ulnar, and median nerves. Noninferiority was assessed using a margin of 20%. Exploratory outcomes included sensory and motor block assessments, time to pain relief, block duration, pain during reduction, patient satisfaction, quality of closed reduction, fracture treatments, and safety. RESULTS: Ropivacaine 0.2% was statistically inferior to ropivacaine 0.5% in achieving block success at 45 min (risk ratio (RR) 0.63, 97.5% CI 0.40-0.99). Lidocaine 1% with epinephrine did not meet the predefined noninferiority criteria for block success (RR 0.95, 97.5% CI 0.73-1.22) but did provide comparable analgesia with a shorter block duration. Pain scores during reduction were low across all groups, with a significant decrease in pain from baseline. Patient satisfaction was high in all groups. No significant differences were found in the quality of closed reduction, safety, or fracture treatments. CONCLUSION: Lateral infraclavicular block with ropivacaine 0.2% failed to demonstrate noninferiority for block success and was statistically inferior to ropivacaine 0.5%. Inferiority testing should be interpreted cautiously within the context of a noninferiority design, although the results suggest reduced effectiveness for distal radius fracture reduction. Lidocaine 1% with epinephrine yielded inconclusive results for noninferiority on block success, but provided a shorter block duration without compromising analgesia, patient satisfaction, or quality of reduction. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT06379490 (released April 23, 2024); https://clinicaltrials.gov/study/NCT06379490; EUCT Identifier 2024-510,572-20-00; https://euclinicaltrials.eu/ctis-public/view/2024-510572-20-00.
Steensbæk et al. (Sat,) studied this question.