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.