Interscalene Block with and without Intraoperative Local Infiltration with Liposomal Bupivacaine in Shoulder Arthroplasty: A Randomized Controlled Trial

Abstract

Background: Interscalene brachial plexus blockade (ISBPB) is an effective anesthetic technique for shoulder arthroplasty; however, "rebound pain" can increase the patient's postoperative pain experience and narcotic usage. Exparel (liposomal bupivacaine) injected into the soft tissues at the surgical site has theoretical efficacy for up to 72 hours after administration. The purpose of this study was to evaluate postoperative pain scores and narcotic consumption following shoulder arthroplasty performed with either ISBPB alone or ISBPB and intraoperative Exparel.

Methods: Seventy-eight patients undergoing primary shoulder arthroplasty were randomized to receive an ISBPB with Exparel (39 patients) or without Exparel (39 patients). The primary outcome variable was morphine equivalent units (MEUs) consumed over the first 24 hours after surgery. Secondary outcomes included intraoperative narcotic administration and visual analog scale (VAS) scores for pain (at 0, 8, 16, 24, 48, and 72 hours after surgery).

Results: There were no significant demographic differences between the ISBPB and ISBPB + Exparel groups. Total narcotic consumption over the first 24 hours after surgery was significantly lower in the ISBPB group compared with the ISBPB + Exparel group (mean and standard deviation, 18.9 ± 25.6 MEU versus 35.3 ± 36.7 MEU, p = 0.009). VAS pain scores did not differ significantly between groups at any time point during the first 72 hours after surgery.

Conclusions: Patients treated with Exparel required significantly more postoperative narcotics and demonstrated no significant reduction in pain scores over the first 72 hours after primary shoulder arthroplasty. Exparel does not appear to have substantial value when added to a pain protocol that includes an ISBPB.

Level of evidence: Therapeutic Level l. See Instructions for Authors for a complete description of levels of evidence.