Comparison of opioid-sparing effect of liposomal vs. nonliposomal bupivacaine for interscalene block in total shoulder arthroplasty: a randomized controlled trial.

Background: Liposomal bupivacaine (LB) was developed to provide longer lasting postoperative analgesia, but its clinical role is still being elucidated. We assessed the opioid-sparing effect of LB in patients undergoing total shoulder arthroplasty (TSA) with an interscalene block (ISB). Methods: Patients scheduled for TSA were randomized to receive either 20 mL of bupivacaine 5 mg/mL control or 10 ml of bupivacaine 5 mg/mL plus LB 133 mg experimental [EXP] for an ISB. The primary outcome was opioid consumption from 24 to 72 hours. The secondary outcomes were cumulative opioid consumption on postoperative days (PODs) 7, 14, and 30 and pain intensity scores measured by the Patient Reported Outcomes Measurement Information System scale. Results: 150 patient results were evaluated as follows: 72 in the control group and 78 in the EXP group. Opioid consumption was lower in the EXP group from 24 to 72 hours (30.4 morphine milligram quivalents ± 30.1 vs. 54.8 ± 36.7; reduction by a factor 1.80, 95% CI: 1.32-2.29; Conclusion: The addition of LB to plain bupivacaine for an ISB is associated with a statistically significant but not clinically meaningful reduction in opioid consumption over the first 72 hours following TSA. These findings should be considered when making an economical decision to use LB.