Curbing the addiction: Pioneer study explores CBD’s potential to reduce opioid use after knee surgery
By Cam Buchan
In what is being called the definitive trial for perioperative use of cannabidiol (CBD), a team from Schulich Medicine & Dentistry and the University of Michigan will undertake a massive study to determine how CBD treatment affects the need for opioid pain medication after knee replacement surgery.
Boosted by a National Institutes of Health (NIH) grant of more than USD $6 million, Dr. Joel Gagnier, associate professor in the Department of Epidemiology and Biostatics and Surgery at Schulich Medicine & Dentistry and colleagues will follow 380 patients in a five-year, multi-site 2x2 factorial clinical trial.
Gagnier with clinical trial and methodologic expertise in orthopaedic clinical trials, along with Dr. Chad Brummett, MD, a professor with expertise in perioperative opioid use and Kevin Boehnke, PhD, an assistant professor with expertise in CBD both in the Department of Anesthesiology at the University of Michigan – will examine whether CBD can also be useful in reducing opioid use, pain and other outcomes before and/or after surgery.
The two major components of cannabis are tetrahydrocannabinol (THC), the main psycho-active component, and cannabidiol (CBD), the major non-psycho-active component. While CBD has some preliminary evidence for reducing pain, through a recent meta-analysis by Gagnier and his team, there has not been a large, rigorous definitive trial to confirm these early findings and related perioperative effects.
“We expect that the patients who take CBD pre- and post-operatively will have decreased need for pain medications, such as opioids, our primary outcome. We also expect to see improvements on measures on physical and psychological functioning,” said Gagnier, who came to Schulich Medicine & Dentistry in 2022 after 12 years at Michigan. “These outcomes will of course, if we see the response we expect, have positive implications for clinical practice in orthopaedic surgery and related surgical disciplines where patients experience pain. Further, we hope this might stem the use and potential for abuse of opioids.”
Joel Gagnier
Associate professor, Department of Epidemiology and Biostatics and Surgery
With the continuing demands of an aging population, more than 1 million total knee arthroplasties (TKAs) are performed annually in the United States while in Canada the annual number stands at approximately 80,000, said Gagnier.
While these procedures are key to improving the quality of life for patients with severe osteoarthritis, they carry the risk of life-threatening addiction to opioids – the primary method for pain treatment after the procedure.
Figures from 2023 paint a tragic picture of opioid dependence in both the U.S. and Canada.
Despite a slight decline in the U.S. in 2023, the overall trend remains alarming, with approximately 100,000 drug overdose deaths (mostly opioid-related) occurring annually. In Canada, the opioid crisis has also reached critical levels, with an average of 22 opioid-related deaths per day or approximately 8,000 deaths annually, largely driven by fentanyl and other synthetic opioids.
There are also significant side effects associated with opioids, such as drowsiness, dizziness and high levels of anxiety.
“There is certainly an opioid crisis in the U.S. and to a lesser degree in Canada,” said Gagnier. “Finding ways to mitigate the use of opioids in recovery is critical in reducing the risk of addiction. CBD use could also extend into other surgical disciplines that have significant pain associated with them – like spinal surgeries or total hip replacements, for example.”
Recruitment is underway at both the University of Michigan in Ann Arbor, and Henry Ford Hospital in Detroit, said Gagnier, with plans to recruit at Western in fall 2025.