The most effective local infiltration analgesic (LIA) in reducing overall opioid use and nausea in the acute postoperative period of shoulder arthroplasty patients; a prospective, double-blind, randomized observational study

Abstract

IntroductionEffective pain management in the immediate postoperative period is a crucial first step in the treatment of shoulder arthroplasty patients. Previous studies suggested that local infiltrative analgesia (LIA), specifically with Liposomal Bupivacaine (LB), is equivalent to interscalene nerve block (ISNB) for postoperative pain management. This prospective, randomized, double-blinded study seeks to measure the difference in efficacy between the 3 widely-used LIA cocktail formulations: Bupivacaine, LB, and Ropivacaine. MethodsBetween 2018 and 2019, 179 consecutive patients underwent reverse total shoulder arthroplasty for end-stage shoulder arthropathy. Patients were enrolled and randomized in a prospective, double-blind clinical trial to receive one of 3 LIA injections before skin incision and after skin closure: 0.25% Bupivacaine ±Epinephrine, 1.3% LB, or 0.5% Ropivacaine cocktail with Ketorolac. There were 67 patients excluded due to preoperative comorbidities or consent refusal. The eligible 112 patients were monitored for 24 hours after surgery. Mean age was 67.9 years (range: 40-90 years). The primary outcome measure was the mean preoperative Visual Analog Scale (VAS) pain score, mean postoperative VAS score during the 24-hour postoperative period, and change in mean VAS score. The secondary outcome measure was total Morphine Milligram Equivalents (MMEs) used, antiemetic use, and laxative use during the same period. Pre-hoc power analysis found a total sample size of 219 (73 per group) was estimated to detect a significant difference at 80% power and 0.05 Type I error rate. ResultsUse of Bupivacaine, LB, and Ropivacaine resulted in 1.2±2.9, 0.6±3.2, and 0.1±2.8 change in VAS scores, respectively (P=.32). Total postoperative MMEs used were 124.1±115.1, 116±84.5, and 105±96.7 milligrams, respectively (P=.71). There were no statistically significant differences amongst the 3 cocktails for postoperative pain relief or rate of antiemetic/laxatives used.There was a nonsignificant trend toward superior analgesic effect of Ropivacaine compared to Bupivacaine. Ad-hoc power analysis found that the estimated sample sizes required to detect a difference between the Ropivacaine and Bupivacaine treatment for change in VAS score and total MMEs use, were 321 and 1593 patients, respectively. Because of the non-clinically significant differences, continued patient enrollment was terminated. The cost of Bupivacaine was comparable to Ropivacaine ($13.43 and $21.95, respectively), whereas LB cost ($434.96) was 20-30 times higher. ConclusionThere were no differences in clinical efficacy amongst Bupivacaine, LB, and Ropivacaine cocktails for perioperative pain management in shoulder arthroplasty. LB was not clinically advantageous compared to the other two medications and did not justify the increase in cost. Level of EvidenceLevel I; Randomized, Controlled Trial