Abstract
Multimodal pain management strategies are critical in total knee arthroplasty (TKA). There has recently been a shift toward opioid sparing protocols, yet most publications continue to use narcotics in the perioperative period. Periarticular injections are a popular adjunct but studies regarding the optimal medications have high variability making it difficult to choose the optimal medication. The purpose of this study is to validate a perioperative, opioid-free protocol and compare two different periarticular injections without the variability in previous reports. A multimodal pain protocol was instituted that administered no narcotic medications in the perioperative period. Over 2 years, primary TKA patients were informally randomized to receive liposomal bupivacaine (LB), or a cocktail of medications (CO). A total of 189 patients were included: 101 patients in group LB and 88 patients in group CO. Postoperative opioid consumption, length of stay, and inpatient distance ambulated were compared across the two injection groups. In morphine milligram equivalents, group LB consumed a mean of 20.36 mg of oxycodone versus 23.18 mg in group CO (p = 0.543). For tramadol, group LB consumed 27.24 mg versus 28.69 mg in group CO (p = 0.714). Mean hospital stay was 1.70 days for group LB and 1.72 days for group CO (p = 0.811). Distance ambulated was 528.4ft for group LB and 499.8ft for group CO (p = 0.477). In the LB group, 50% of patients required no oxycodone, and 12% of them took neither oxycodone nor tramadol for pain. In the CO group, 40% declined oxycodone and 10% declined both oxycodone and tramadol. We successfully treated all patients without narcotic medications in the perioperative period. Although we saw trends for improvements in group LB, these were small and not clinically meaningful. It appears that both injections were effective. There is a significant cost difference and medications should be chosen based on surgeon preference and institutional needs.
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