Increasing the volume of pericapsular nerve block may not improve postoperative pain control after total hip arthroplasty

1. Higher-volume pericapsular nerve group block did not provide better postoperative analgesia than the conventional-volume block after primary total hip arthroplasty.

2. Increasing the block volume also did not clearly worsen quadriceps weakness or improve opioid use, ambulation, or length of stay.

Evidence Rating Level: 1 (Excellent)

In this single-center randomized controlled trial, investigators evaluated whether a high-volume pericapsular nerve group block improves analgesia after primary total hip arthroplasty compared with a conventional-volume block. The rationale was that postoperative pain after total hip arthroplasty can be substantial, and although the pericapsular nerve group block may preserve motor function better than other regional techniques, the optimal injectate volume remains uncertain. Adults undergoing primary unilateral total hip arthroplasty under spinal anesthesia were randomized to receive either 40 mL or 20 mL of 0.375% ropivacaine with dexamethasone. The primary outcome was dynamic pain at 6 hours postoperatively; secondary outcomes included pain at other time points, sensory and motor block, opioid use, time to first ambulation, length of stay, and complications. Of 40 randomized patients, 37 were analyzed. High-volume blockade did not improve the primary outcome: median dynamic pain scores at 6 hours were 5 in the high-volume group and 4 in the conventional-volume group. There were also no significant differences in static or dynamic pain at 3 or 24 hours, opioid consumption over 48 hours, time to first walking, hospital length of stay, sensory blockade, motor weakness, or adverse events. The authors concluded that a high-volume pericapsular nerve group block was not superior to the conventional-volume approach for postoperative analgesia after primary total hip arthroplasty.

Click here to read the study in PLOS One

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