Opioids are a mainstay in perioperative pain management among patients undergoing total knee arthroplasty (TKA). However, patterns in opioid use before and after TKA have not been well-studied. The objectives of this study are to characterize prescribing trends preoperatively and postoperatively and identify risk factors for chronic postoperative opioid use.
A review of the prescription-tracking database of a large private payer from 2007 to 2013 was performed using International Classification of Diseases, Ninth Revision and Current Procedural Terminology codes. Chronic opioid use was defined as opioid prescriptions over 6 contiguous months postoperatively.
We identified 66,950 patients who underwent TKA with minimum 2-year follow-up and medication codes. Of those taking opioids preoperatively (n = 36,668), 34.8% became chronic users postoperatively compared to only 5.0% of the opioid-naïve cohort (n = 30,282). Major risk factors for chronic postoperative opioid use included preoperative opioid use (relative risk [RR] 3.75, 95% confidence interval [CI] 3.59-3.93), female gender (RR 1.23, 95% CI 1.20-1.25), and younger age (≤44 vs ≥60: RR 1.41, 95% CI 1.32-1.49; 45-59 vs ≥60: RR 1.42, 95% CI 1.40-1.46). From 2007 to 2013, there was a significant linear increase in opioid use preoperatively (odds ratio [OR] 1.04, 95% CI 1.03-1.05, P < .001) and postoperatively (OR 1.20, 95% CI 1.18-1.21, P < .001), but chronic postoperative opioid use increased only marginally (OR 1.01, 95% CI 1.00-1.02, P = .021).
The greatest risk factors for chronic postoperative opioid use were preoperative use, younger age, female gender, greater length of stay, and worse health status. Although the use of opioids continues to grow significantly preoperatively and postoperatively, chronic opioid use post-TKA has remained clinically unchanged.