Analgesic Efficacy of Interscalene Nerve Block Versus Local Infiltration Analgesia Following Total Shoulder Arthroplasty

Prospective, Randomized Controlled Trial Comparing Analgesic Efficacy of Single Injection vs. Continuous Interscalene Blockade vs. Local Infiltration Analgesia for Patients Undergoing Primary Total Shoulder Arthroplasty

Total shoulder arthroplasty (TSA) is considered to be a major surgical procedure resulting in severe postoperative pain, especially in the first 48 hours after surgery. The use of interscalene brachial plexus nerve block remains the cornerstone for analgesia following shoulder surgery; however, with the advent of local infiltration analgesia (LIA), there has been increasing interest in its use for total joint arthroplasty.

Since the benefits of local infiltration analgesia within a comprehensive multi-modal analgesia clinical pathway have yet to be established for total shoulder arthroplasty, the Investigators plan to assess and compare analgesia outcomes between three intervention groups: single shot interscalene brachial plexus block (SISB), continuous interscalene brachial plexus block (CISB), and local infiltration analgesia (LIA).

Inclusion criteria:

1. Adult patients with an American Society of Anesthesiologists (ASA) physiological status I-III
2. Patients presenting for unilateral primary total shoulder arthroplasty (includes anatomic and reverse total shoulder arthroplasty).
3. Patients 18 years of age and older
4. Able to provide informed consent for him or herself

Exclusion Criteria:

1. Chronic pain syndromes such as fibromyalgia or complex regional pain syndrome

2. Chronic opioid use (>1 mos) with oral morphine equivalents (OME) >5 mg/day OR acute opioid use (< 1 mos) with OME > 30 mg/day.

3. Body mass index (BMI) > 45 kg/m2

4. Severe drug allergy* to medications used in this study, including non-steroidal anti-inflammatory drugs (i.e. celecoxib and ketorolac), and local anesthetics.

5. History of Malignant Hyperthermia.

6. Major systemic medical problems such as:

   • Pre-existing severe renal disorder defined as glomerular filtration rate (GFR) <50 units/m2 (if labs are available), currently on dialysis, or highly suspected based on history.
   • Severe hepatic disorder defined as current or past diagnosis of acute/subacute necrosis of liver, acute hepatic failure, chronic liver disease, cirrhosis (primary biliary cirrhosis), chronic hepatitis/toxic hepatitis, liver abscess, hepatic coma, hepatorenal syndrome, other disorders of liver
   • Pre-existing medical history of moderate to severe pulmonary disease (obstructive and/or restrictive), use of home oxygen, preoperative baseline oxygen saturation < 94% on room air, forced expiratory volume in 1 second (FEV 1) < 60% of predicted value (obstructive disease), vital capacity (VC) or total lung capacity (TLC) < 70% predicted value (restrictive disease).37
   • History of contralateral hemidiaphragmatic dysfunction (e.g., paralysis) or phrenic nerve injury.

7. Contraindication to a regional anesthesia technique (e.g., preexisting neuropathy+ in the operative extremity, coagulopathy, sepsis, infection at site of injection, uncooperative, refusal, anticoagulation medications not held within appropriate time frame per American Society of Regional Anesthesia (ASRA) guidelines.

8. Previous contralateral total shoulder replacement managed with regional anesthetic nerve block or periarticular injection/intraarticular injection within the previous 12 months.

9. Known to be currently pregnant or actively breastfeeding++

   • ++ Patients that have a previous history of menopause, hysterectomy, or tubal ligation will not be required to perform a pregnancy test.

10. Impaired cognition