Early postoperative opioid consumption following liposomal bupivacaine compared to standard bupivacaine in interscalene brachial plexus block for shoulder arthroplasty

Background: To retrospectively compare early postoperative opioid consumption in patients undergoing shoulder arthroplasty who receive an interscalene brachial plexus nerve block with either standard or liposomal bupivacaine. Methods: A retrospective review was performed at a large multicenter health-care system. Patients included those who underwent primary total shoulder arthroplasty or reverse shoulder arthroplasty between January 2021 and January 2024, were aged 18-99 at the time of hospital admission, had a primary diagnosis of osteoarthritis, and received an interscalene brachial plexus nerve block using either standard bupivacaine or liposomal bupivacaine before surgery. The primary outcome was opioid usage, measured in morphine milligram equivalents (MMEs). Secondary outcomes were length of stay and readmission rate. Results: A total of 870 patients were included in the study. Liposomal bupivacaine was associated with a statistically significant reduction in opioid consumption at postoperative day 0 (median: 0.0 vs. 7.5 MME, P < .001), day 1 (0.0 vs. 15.0 MME, P < .001), and cumulatively during admission (4.0 vs. 25.2 MME, P < .001). Reductions in opioid consumption on postoperative day 1 and during the entire admission were judged to be clinically significant. Patients receiving liposomal bupivacaine were much more likely to receive 0 MME during their admission (relative risk: 2.84, 95% confidence interval: 2.23-3.63, P < .001). Patients who received liposomal bupivacaine had shorter admissions compared to control (1.19 ± 0.70 days vs. 1.38 ± 1.24 days, P = .01). There were no differences in readmission rate (P = .83) or time to readmission (P = .73) between groups. Conclusion: Liposomal bupivacaine delivered via interscalene brachial plexus block was shown to significantly reduce immediate postoperative opioid consumption and length of stay compared to standard bupivacaine before shoulder arthroplasty. Furthermore, patients receiving liposomal bupivacaine were more likely to be opioid-free during their surgical admission.