Risk factors for liposomal bupivacaine resistance after total hip or knee arthroplasties: a retrospective observational cohort in 237 patients

PURPOSE: Liposomal bupivacaine demonstrated promise decreasing postoperative pain in total hip and total knee arthroplasty (THA/TKA). Some randomized trials have shown non-superior results; however, confounding variables were not accounted for in such analyses. This study attempts to determine risk factors associated with failure of pain management in patients receiving liposomal bupivacaine. METHODS: Postoperative pain scores were collected following primary or revision arthroplasties between January 2016 and December 2017. Retrospective analysis of institutional total joint quality and outcomes registry was screened and patients undergoing primary or revision arthroplasties who completed a multi-modal pain management including liposomal bupivacaine were included in the study. Patients with a history of infection/deviated from the institutional pain management protocol were excluded. RESULTS: A total of 237 patients were included for analysis. Younger patients less than 64 years old had significantly higher pain scores between 0 and 12 h and > 24 h. Active smokers had significantly higher pain scores between 0 and 6 h and > 24 h. Patients with a history of opioid use/pain management had significantly higher pain scores at 6-12 h and 24-48 h. Regression analysis indicated risk factors for resistance to liposomal bupivacaine are younger patients less than 64 years old, those undergoing primary THA, and patients with a history of smoking/pain management/opioid use. CONCLUSION: We identify risk factors for resistance to liposomal bupivacaine, which include younger age less than 64 years old, history of smoking/pain management/opioid use. Future studies should use these risk factors as exclusion criteria when using liposomal bupivacaine or initiating any randomized trials regarding efficacy.