Single-Shot Versus Continuous Interscalene Block for Postoperative Pain Control After Shoulder Arthroplasty: A Prospective Randomized Clinical Trial

INTRODUCTION: Continuous catheter infusion of local anesthetics extends the efficacy of regional anesthesia after prosthetic shoulder surgery. Our purpose was to compare continuous interscalene block (CIB) with single-shot interscalene block, and the hypothesis was these would offer similar safety and efficacy in patients with prosthetic shoulder arthroplasty. METHODS: Seventy-six patients were randomized to ropivacaine single-shot interscalene block or CIB after prosthetic shoulder arthroplasty. Postoperative pain scores and opioid use, hospital length of stay (LOS), adverse events, and catheter tip withdrawal were recorded. RESULTS: Pain scores (P = 0.010) and opioid use (P = 0.003) on the first postoperative day were lower in the CIB group, but there was no difference in LOS. Adverse events were more common in the CIB group and 10% of catheters pulled out prematurely. CONCLUSION: Opioid use and pain levels during first postoperative day are clinically less after CIB, but this did not shorten LOS. The benefits of CIB may not justify the higher cost and complication rate.