Lower Post-op Opioid Use Has Little Effect on Pain Scores After TKA

Author: Anna DeNelsky

Anesthesiology News

Data from the Opioid Safety Initiative implemented at the Veterans Health Administration revealed that a reduction in patients’ prescription opioids after knee replacement surgery did not translate to a significant improvement in pain scores, according to new research published in Anesthesiology (2019;131[2]:369-380).

Chronic pain is frequent in patients undergoing total knee arthroplasty (TKA), and the operation is performed often throughout the United States. Researchers sought to determine whether the VA initiative would show a correlation between opioid use and improvement in pain scores.

Group-level data were gathered from over 60,000 TKA patients between 2010 and 2015. Researchers analyzed trends in pain score self-reports and in chronic opioid and nonopioid prescriptions, before and after the implementation of the Opioid Safety Initiative (OSI).

After allowing for opioid use in the first three months after TKA, the OSI decreased subsequent prescriptions by about 20% (871 fewer individuals with postoperative prescriptions; 95% CI, 474-1,268), a statistically significant reduction. Mortality rates among the study population were also reduced (pre-OSI intervention, n=31,547; post-intervention, n=28,509).

Postoperative pain scores, however, increased slightly following the safety initiative, from 0.65 to 0.81 (95% CI, 0.05-0.27).

“Average pain scores measured over six months after surgery were essentially unchanged,” said Karthik Raghunathan, MD, MPH, an associate professor of anesthesiology at Duke University Medical Center, in Durham, N.C., in a press release. “This work at the VA may inform ongoing efforts to counter the opioid epidemic across the country.”

He suggested that the slight increase in average pain scores might be due to the “relatively modest effect that opioids have on chronic pain after surgery.” Furthermore, results showed that the use of nonopioid medication increased, which according to Dr. Raghunathan may reduce the effect of decreasing opioid use.

The OSI is based on chronic pain clinical treatment guidelines developed by the VA and the Department of Defense, and tracks opioid prescriptions at national, regional, and facility and provider levels.