Liposomal Bupivacaine (Exparel ® ) Plus 0.5% Bupivacaine HCL Versus 0.5% Bupivacaine HCL for Interscalene Nerve Block (ISB) for Patients Undergoing Total Shoulder Arthroplasty(TSA)

This is a phase IV , randomized, single-blind, single-center study comparing patient related outcomes such as postoperative pain and opioid usage for patients who receive ISB 's containing liposomal bupivacaine (Exparel®) plus 0.5% bupivacaine HCL versus 0.5% bupivacaine HCL undergoing total shoulder arthroplasty. The objective of this study is to compare opioid utilization and pain management of patients who receive Exparel in an ISB vs standard 0.5% bupivacaine HCL during the initial 72 --- hour post --- operative period. Additionally, to understand the duration of block after addition of Exparel® to bupivacaine in an Interscalene block after TSA.