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.

Inclusion Criteria:

• Patients undergoing total shoulder arthroplasty;
• Patients who consent to be randomized.

Exclusion Criteria:

• Patients younger than 18 and older than 75;
• Patients with a history of chronic pain that have used opioids for pain management for 3 months or longer;
• Patients who are allergic to oxycodone;
• Patients who are unable to speak English;
• Patients with diagnosed or self---reported cognitive dysfunction;
• Patients with a history of neurologic disorder that can interfere with pain sensation;
• Patients with a history of drug or recorded alcohol abuse;
• Patients who are unable to understand or follow instructions;
• Patients with severe liver disease, renal insufficiency, congestive heart failure, and/or significant heart disease;
• Patients with an allergy or contraindication to any of the medications used in the study, or patients with a contraindication to any study procedures;
• Patients with BMI over 40;
• Any patient that the investigators feel cannot comply with all study related procedures;
• NYU Langone Health students, residents, faculty or staff members

Individual participant data that underlie the results reported in this article, after deidentification (text, tables, figures, and appendices). Data will be available to achieve aims in the approved proposal.

Immediately following publication. No end date

Requests should be directed to uchenna.umeh@nyulangone.org. To gain access, data requestors will need to sign a data access agreement.

Access will be given to researchers who provide a methodologically sound proposal and investigators whose proposed use of the data has been approved by an independent review committee ("learned intermediary") identified for this purpose.