Risk Factors and Trajectories of Opioid Use Following Total Knee Replacement

Background: Opioids are commonly used to manage orthopedic pain in those undergoing total knee arthroplasty (TKA). There are limited studies assessing patterns of perioperative opioid use and risk factors for chronic use in patients undergoing TKA.

Methods: This is a retrospective longitudinal cohort study of Medicaid enrollees undergoing TKA between 2014 and 2017 using de-identified medical and pharmacy claims. The primary outcome was chronic opioid use (opioid prescription filled 90-270 days following TKA). Trajectory group membership was determined by identifying distinct groups of patients with similar patterns of daily morphine milligram equivalent (MME) values during the postsurgery follow-up period.

Results: In total, 1666 TKA surgeries performed in 1507 patients were included; 69% of patients were classified as chronic opioid users. Multivariable analyses identified prior opioid use, high opioid doses during the month after TKA, concomitant mood therapies and benzodiazepines, and comorbid conditions as important risk factors. Group-based trajectory analysis identified five distinct post-TKA surgery opioid use phenotypes with several key characteristics predicting group membership.

Conclusions: This large-scale analysis demonstrated that chronic opioid use was common after TKA surgery and established several important risk factors for chronic use following TKA. Novel analysis revealed five distinct opioid use trajectories and identified key characteristics to help guide clinicians when determining perioperative opioid use. Results demonstrate that interventional studies attempting to reduce opioids after TKA are needed if reductions in long-term use are to be realized in this high-risk patient population.