Randomized Clinical Trial Comparing Mixed Liposomal Bupivacaine versus Continuous Catheter for Interscalene Block during Shoulder Arthroplasty: A Comparison of Analgesia, Patient Experience, and Cost

Background: Continuous interscalene catheters extend analgesia beyond 24 hours but are resource-intensive, while the efficacy of liposomal bupivacaine for single-injection interscalene blocks remains uncertain. The purpose of this investigation was to examine the analgesic efficacy, quality of recovery, and treatment costs between interscalene nerve block using either an indwelling catheter or single shot block using liposomal bupivacaine, in patients undergoing shoulder arthroplasty.

Methods: In this single-center, parallel, unblinded, randomized clinical trial, 83 patients undergoing primary shoulder arthroplasty were assigned to either a continuous interscalene catheter group (n=44) or a single-injection liposomal bupivacaine interscalene block group (n=39). The interscalene catheter group received a 15-20 mL bolus of 0.5% bupivacaine HCl followed by continuous infusion at 8 mL/h for 69 hours. The single-injection interscalene group received 10 mL (133 mg) liposomal bupivacaine with 5 mL of 0.5% bupivacaine HCl. The primary outcome was pain at rest 24 hours post-surgery. Secondary outcomes included pain scores, opioid consumption, complications, quality of recovery, and a time-driven activity-based cost analysis through postoperative day 3.

Results: There was no significant difference in median pain scores at 24 hours between the continuous interscalene catheter group and the single-injection liposomal bupivacaine group (1.0 [0.0, 2.0] vs. 1.0 [0.0, 3.0]; P=0.433). Comparable analgesia was observed through postoperative day 3, with no differences in opioid consumption or quality of recovery. No serious adverse events were reported; however, 16% of patients in the continuous catheter group experienced dislodgement or leakage. Liposomal bupivacaine was associated with a 28% reduction in costs compared to the continuous catheter approach.

Conclusion: Single-injection interscalene block with liposomal bupivacaine provides comparable analgesia to continuous interscalene catheters through postoperative day 3 while offering better value in the perioperative management of shoulder arthroplasty patients.