Analgesia After Total Shoulder Arthroplasty

Phase 4

Completed

Interventions: Procedure: Interscalene Block (ISB) - 0.2% Ropivacaine + additives
Procedure: Interscalene Block (ISB) - Systemic Control
Procedure: Interscalene Block (ISB) - 0.375% Ropivacaine + additives
Procedure: Interscalene Block (ISB) - 0.1% Ropivacaine + additives

Brief Summary: The purpose of this study is to determine which medication(s) should be included in the interscalene nerve block (an injection of local anesthetic \[numbing medicine\] near nerves in the shoulder) for patients undergoing total shoulder arthroplasty (shoulder replacement). The ideal nerve block would reduce pain after shoulder surgery without causing a great deal of muscle weakness.

Detailed Description: 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.

Recruitment & Eligibility

Inclusion Criteria

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

Arm && Interventions

Group	Intervention	Description
Interscalene Block (ISB) - 0.2% Ropivacaine + additives	Interscalene Block (ISB) - 0.2% Ropivacaine + additives	-
Interscalene Block (ISB) - Systemic Control	Interscalene Block (ISB) - Systemic Control	-
Interscalene Block (ISB) - 0.375% Ropivacaine + additives	Interscalene Block (ISB) - 0.375% Ropivacaine + additives	-
Interscalene Block (ISB) - 0.1% Ropivacaine + additives	Interscalene Block (ISB) - 0.1% Ropivacaine + additives	-

Primary Outcome Measures

Name	Time	Method
Numeric Rating Scale (NRS) Pain Score With Movement	24 hours after the interscalene block is given	Pain with movement at 24 hours from the nerve block (scale of 0-10; 0 = no pain, 10 = worst possible pain)

Secondary Outcome Measures

Name	Time	Method
Duration of Analgesia From Interscalene Nerve Block	Postoperative day 1 at 8AM & 5PM, postoperative day 2 at 8AM & 5PM	Median time until a patient needed to take opioid pain medication
Numeric Rating Scale (NRS) Pain Scores at Rest	Preop	Assessment of NRS pain scores (scale of 0-10; 0 = no pain, 10 = worst possible pain) at rest
Middle Deltoid	24 hours after surgery	A physical assessment will be done to determine the strength of the middle deltoid muscle in the operative arm using a dynamometer