Perioperative Pain Management for Total Shoulder Arthroplasty: A Pilot Non-Inferiority Trial

A noninferiority clinical trial will be utilized for the study. Eighty patients undergoing primary TSA (anatomic or reverse TSA) with an orthopaedic surgeon at the Roth McFarlane Hand and Upper Limb Centre will be recruited into the study. The study participants (n=80) will be randomized preoperatively into either 1) the ultrasound guided ISB group (n=40) or 2) the high-volume LIA group (n=40). For the pilot study, the investigators will also measure recruitment rates, time to study completion, and drop-out rates.

All patients will undergo TSA through a standard deltopectoral approach. Postoperative rehabilitation will include routine protocols including sling protection for 6 weeks and the following progressive exercises: sling, pendulum, active-assisted range of motion, active range of motion, passive range of motion and shoulder girdle strengthening. Patients randomized to the ultrasound guided ISB group will receive brachial plexus blockade with 10 ml of 0.5% ropivacaine using a high frequency linear array transducer (Sonosite Edge II, FUJIFILM Sonsonite, Inc., Bothell, WA, USA). Patients randomized to the high-volume LIA group will receive 100 mL of 0.9% normal saline (57ml), 0.5% ropivacaine (40 ml), 10 mg morphine (10 mg/ml), 0.1 mg of epinephrine (0.1 mg/ml), and 30 mg of ketorolac (30 mg/ml) divided equally into a 20 ml five-zone field infiltration into the suprascapular notch/posterior capsule (suprascapular and axillary nerves), coracobrachialis muscle, anterior deltoid muscle, superior pectoralis major muscle, and skin incision at the conclusion of the procedure by the treating surgeon. Patients will be discharged with a standard prescription of multimodal analgesics including acetaminophen, ibuprofen, sustained release morphine, and short acting opioid.

In this case, because the LIA option is likely associated with lesser cost and lower risk of adverse events, non-inferior effectiveness for pain control would provide sufficient and clear evidence that the LIA is the preferred choice. The trial will follow CONSORT reporting guidelines . All measures will be administered though our Methods Centre web-based data collection and will be completed in clinic under the direction of a study coordinator. If a patient misses a follow-up, the web-based system will allow us to capture the outcome measures remotely. While investigators have selected multiple secondary outcome measures, they reflect important secondary dimensions and are measured with well-validated short forms that have low response burden. Potential mediators: Sex, age, gender-related pain expectations, occupation, and comorbid health status will be recorded as potential covariates. Sample size estimation: The criteria for sample size requirements for noninferiority trials is based on the smallest difference that is considered clinically relevant and the standard deviation expected from the sample. n=80 participants (n=40 per group) is a conservative estimate based on the ability to detect a moderate effect between study groups for a mean between-groups difference in the primary outcome .