Single Shot Interscalene Block with Liposomal Bupivacaine versus Non-Liposomal Bupivacaine in Shoulder Arthroplasty.

Background: Regional anesthesia is a valuable component of multimodal pain control in total shoulder arthroplasty (TSA), and multiple interscalene block anesthetic options exist, including non-liposomal interscalene bupivacaine (NLIB) and liposomal interscalene bupivacaine (LIB). The purpose of the current of study was to compare pain control and opioid consumption within 48 hours postoperative in those undergoing TSA with either LIB or NLIB.

Methods: This was a retrospective cohort study at a single academic medical center including consecutive patients undergoing inpatient (>23-hour hospitalization) primary anatomic or reverse TSA from 2016 to 2020 who received either LIB or a NLIB for perioperative pain control. Perioperative patient outcomes were collected including pain levels and opioid usage, as well as 30- and 90-day ED visits or readmissions. The primary outcome was postoperative pain and opioid use.

Results: Overall, 489 patients were included in this study (316 LIB and 173 NLIB). Pain scores at 3, 6, 12, and 48 hours postoperatively were not statistically significantly different (p>0.05 for all). However, the LIB group had improved pain scores at 24- and 36-hours postoperative (p<0.05 all). There was no difference in the incidence of severe postoperative pain, defined as a 9 or 10 NRS-11 score, between the two anesthesia groups after adjusting for preoperative pain and baseline opioid use (OR: 1.25; 95% CI: 0.57-2.74; p=0.57). Overall, 99/316 (31.3%) of patients receiving LIB did not require any postoperative opioids compared with 38/173 (22.0%) receiving NLIB; however, this difference was not statistically significant after adjusting for prior opioid use and preoperative pain (p=0.33). No statistically significant differences in postoperative total morphine equivalents or mean daily morphine equivalents consumed between the groups were found during their hospital stays (p>0.05 for both). Finally, no significant differences in 30- and 90-day ED visits or readmission rates were found (all p>0.05).

Conclusion: LIB and NLIB demonstrated differences in patient reported pain scores at 24- and 36-hours post operation, although these did not reach clinical significance. There were no statistically significant differences in opioid consumption during the hospital stay, including opioid use, total morphine equivalents and daily mean morphine equivalents consumed during the hospital stay. Additionally, no differences were observed in 30- and 90-day ED visits or readmission rates.