Analgesia After Total Shoulder Arthroplasty

All patients will receive an intravenous pain pump (patient-controlled analgesia) and a nerve block with long-lasting local anesthetic. The three study groups will receive additives (clonidine, dexamethasone, buprenorphine plus local anesthetic) in the nerve block that may reduce postoperative pain. One of the study groups uses the usual concentration of local anesthetic, while the other two study groups use reduced concentrations of local anesthetic. Follow-up with study patients begins on the day of surgery and continues through postoperative day 2. Seen twice daily, patients will be asked about their pain and assessed for sensory function and strength of their shoulder muscle and hand grip.

Inclusion criteria

• Patients with osteoarthritis
• Primary total shoulder arthroplasty
• Age 18 to 80 years old
• Planned use of general anesthesia
• Planned use of a brachial plexus nerve block for postoperative analgesia
• Ability to follow study protocol

Exclusion criteria

• Patients younger than 18 years old and older than 80
• Allergy or intolerance to one of the study medications
• Patients with an American Society of Anesthesiologists (ASA) physical status of IV
• Patients with insulin-dependent diabetes
• Patients with hepatic (liver) failure
• Patients with chronic renal (kidney) failure
• Bradycardia (heart rate < 50) or hypotension (systolic blood pressure < 90 mmHg)
• Chronic opioid use (taking opioids for longer than 3 months) (or active diagnosis of complex regional pain syndrome [CRPS]/reflex sympathetic dystrophy [RSD])
• Lack of English fluency