Background: Liposomal bupivacaine (LB) theoretically is longer-acting compared with conventional bupivacaine. The purpose of this study was to compare conventional bupivacaine combined with dexamethasone (control group), LB combined with conventional bupivacaine (LB group), and LB combined with dexamethasone and conventional bupivacaine (LBD group) in a perineural interscalene nerve block during ambulatory arthroscopic rotator cuff repair to determine if LB decreased postoperative narcotic consumption and pain. The effect of supplemental dexamethasone on prolonging the analgesic effect of LB was also assessed.
Methods: This was a prospective, double-blinded, randomized controlled trial of 76 consecutive patients who underwent outpatient arthroscopic rotator cuff repair. Patients were randomized into the 3 interscalene-block treatment groups: control group (n = 26), LB group (n = 24), and LBD group (n = 26). Outcome measures included pain measured with a visual analog scale (VAS; 0 to 10) and narcotic consumption measured in oral morphine milligram equivalents (MME). Both were measured daily on postoperative day 0 through postoperative day 4.
Results: Generalized estimating equation modeling revealed that narcotic consumption across all time points (postoperative days 0 to 4) was significantly lower in the LB group compared with the control group (mean difference, -8.5 MME; 95% confidence interval, -15.4 to -1.6; p = 0.015). Narcotic consumption was significantly higher in the control group on postoperative days 2 and 3 compared with the LB group (p = 0.004 and p = 0.02, respectively) and the LBD group (p = 0.01 and p = 0.003, respectively). There was no difference in narcotic consumption between the LBD and LB groups on any postoperative day. VAS pain scores in all groups were similar across all postoperative days.
Conclusions: Among patients undergoing outpatient arthroscopic rotator cuff repair, the addition of LB to conventional bupivacaine in interscalene nerve blocks appeared to be effective in controlling postoperative pain. Because LB with and without dexamethasone decreased postoperative narcotic use, LB should be considered for use in preoperative interscalene nerve blocks to reduce the reliance on narcotics for pain management.
Level of evidence: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.