Randomized Clinical Trial of Exparel vs Pain Pump for Post-operative Pain Control After Total Shoulder Arthroplasty

The primary objective of this study is to determine if Exparel leads to better pain scores at 24, 48 and 72 hours after Total Shoulder Arthroplasty (TSA) compared to a pain pump. Secondary objectives are (1) to determine if patients on Exparel use less narcotics and (2) have earlier return of functional use of the involved arm after surgery compared to the pain pump and (3) if use of Exparel leads to cost savings

METHODS

Sample size:

Based on prior studies on anesthetics for TSA, the mean worst pain score in the 24 hours after surgery was 5.4, based on a 0 to 10 scale. To detect a change of 2 points, alpha of 0.05, beta of 0.80, a sample size of 51 subjects in each group will be required. To account for drop-outs, a total of 60 subjects in each arm will be enrolled.

Inclusion criteria Patients undergoing unilateral primary TSA or reverse TSA Indication for surgery is osteoarthritis, rotator cuff arthropathy or massive irreparable rotator cuff tears Surgery performed by the Principal Investigator Anesthesia administered by Co-Principal Investigator Willing and able to sign an Informed Consent Exclusion criteria Indication for surgery is fracture Comorbid psychiatric diagnosis requiring therapy and/or medication except anxiety or depression Comorbid chronic pain syndrome (reflex sympathetic dystrophy, fibromyalgia) Has hepatic disease On workers compensation/disability/litigation Known adverse reaction to medications to be administered On long-acting narcotic pain medication (including extended release narcotic pain medications and methadone) Home Oxygen requirement whether as needed or scheduled. Contralateral Phrenic Nerve paralysis / incompetence. Body Mass Index ≥ 50 Randomization will be a varied blocked randomization with blocks of 12, 15 and 18 using sealed envelopes

Treatment arms:

Control: Pain catheter based pain control. Subject will receive an interscalene block with Ropivicaine 0.5% (20cc), and then a pain pump attached in the Post Anesthesia Care Unit infusing at 4cc/hr. The patient will go home with that device until it runs out.

Interventional: Single shot Exparel 10cc (133mg) mixed with 10cc of 0.5% Bupivicaine

Both arms will receive the same multimodal analgesia medications preoperatively. Celebrex 400mg PO, Gabapentin 600mg PO, Tylenol 1 gram PO, unless contraindicated.