BACKGROUND

Prolonged opioid use following total knee arthroplasty (TKA) has not been extensively studied.

METHODS

A cohort study of primary TKA for osteoarthritis using an integrated healthcare system and Total Joint Replacement Registry (January 2008-December 2011) was conducted. Opioid use during the first year after TKA was the exposure of interest and cumulative daily oral morphine equivalent (OME) amounts were calculated. Total postsurgical OME per 90-day exposure periods were categorized into quartiles. The end point was aseptic revision surgery. Survival analyses were conducted and hazard ratios (HRs) were adjusted for age, gender, prior analgesic use, opioid-related comorbidities, and chronic pain diagnoses.

RESULTS

A total of 24,105 patients were studied. After the initial 90-day postoperative period, 41.5% (N = 9914) continued to use opioids. Also, 155 (0.6%) revisions occurred within 1 year and 377 (1.6%) within 5 years. Compared to patients not taking any opioids, patients using medium-low to high OME after the initial 90-day period had a higher adjusted risk of 1-year revision, ranging from HR = 2.4 (95% confidence interval, 1.3-4.5) to HR = 33 (95% confidence interval, 10-110) depending on the OME and time period.

CONCLUSION

Patients who require opioids beyond 90 days after TKA warrant close follow-up.