Analgesia After Total Shoulder Arthroplasty

Study Overview
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Brief Summary
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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
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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.

Official Title
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Analgesia After Total Shoulder Arthroplasty

Conditions
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Total Shoulder Arthroplasty

Intervention / Treatment
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* Procedure: Interscalene Block (ISB) - 0.375% Ropivacaine + additives
* Procedure: Interscalene Block (ISB) - 0.2% Ropivacaine + additives
* Procedure: Interscalene Block (ISB) - 0.1% Ropivacaine + additives
* Procedure: Interscalene Block (ISB) - Systemic Control


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Interscalene Block (ISB) - 0.375% Ropivacaine + additives<br> | Procedure: Interscalene Block (ISB) - 0.375% Ropivacaine + additives<br>* Ultrasound-guided single-injection ISB: ropivacaine 0.375% + (clonidine [100 mcg] + dexamethasone [4 mg] + buprenorphine [150 mcg]); Intravenous (IV): saline<br>|
| Active Comparator: Interscalene Block (ISB) - 0.2% Ropivacaine + additives<br> | Procedure: Interscalene Block (ISB) - 0.2% Ropivacaine + additives<br>* Ultrasound-guided single-injection ISB: ropivacaine 0.2% + (clonidine [100 mcg] + dexamethasone [4 mg] + buprenorphine [150 mcg]); Intravenous: saline<br>|
| Active Comparator: Interscalene Block (ISB) - 0.1% Ropivacaine + additives<br> | Procedure: Interscalene Block (ISB) - 0.1% Ropivacaine + additives<br>* Ultrasound-guided single-injection ISB: ropivacaine 0.1% + (clonidine [100 mcg] + dexamethasone [4 mg] + buprenorphine [150 mcg]); Intravenous: saline<br>|
| Active Comparator: Interscalene Block (ISB) - Systemic Control<br> | Procedure: Interscalene Block (ISB) - Systemic Control<br>* Ultrasound-guided single-injection ISB: ropivacaine 0.375%; Intravenous: clonidine (100 mcg) + dexamethasone (4 mg) + buprenorphine (150 mcg)<br>|

What is the study measuring?
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Primary Outcome Measures

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

Secondary Outcome Measures

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