Cannabinoids vs. Placebo on Persistent Post-surgical Pain Following TKA: A Pilot RCT

Trial details

Who runs it

McMaster University

Trial code

NCT03825965

Record updated

22 October 2026

Original description

Each year, approximately 75,000 Canadians undergo knee replacement surgery, and up to 25% develop persistent post-surgical pain. Persistent post-surgical pain is associated with depression, anxiety, unemployment, and reduced quality of life. Chronic pain after surgery is often managed with opioid therapy, which typically provides only modest benefits and is associated with rare but serious adverse events, such as overdose and death. A number of studies have found that greater pain just before and after knee replacement surgery is associated with the development of chronic pain, suggesting that reducing peri-operative pain may help prevent persistent post-surgical pain.Read full original descriptionShow less

The Effect of Cannabinoids vs. Placebo on Persistent Post-surgical Pain Following Total Knee Arthroplasty: A Multicenter, Randomized Pilot Trial

Each year, approximately 75,000 Canadians undergo knee replacement surgery, and up to 25% develop persistent post-surgical pain. Persistent post-surgical pain is associated with depression, anxiety, unemployment, and reduced quality of life. Chronic pain after surgery is often managed with opioid therapy, which typically provides only modest benefits and is associated with rare but serious adverse events, such as overdose and death. A number of studies have found that greater pain just before and after knee replacement surgery is associated with the development of chronic pain, suggesting that reducing peri-operative pain may help prevent persistent post-surgical pain.

Medicinal cannabis has begun to emerge as a potential therapy for pain reduction, and produces effects largely due to 2 active components: (1) cannabidiol (CBD), and (2) tetrahydrocannabinol (THC). Studies of CBD have shown analgesic, anti-inflammatory, and anti-anxiety properties, but without the psychoactive effects (feeling 'high') that THC produces. This study will assess the feasibility of a definitive trial to explore whether adding CBD dominant vs. placebo to usual care before and after surgery can reduce the rate of persistent post-surgical pain after total knee replacement. This study will randomize 40 patients to receive either CBD dominant or placebo, and follow them for six months to confirm our ability to recruit patients, adhere to protocol, and capture full outcome data for at least 85% of patients.

Inclusion: Patients undergoing TKA aged 18 or older; Cognitive ability and English-language skills required to complete outcome measures; Provision of informed consent; Successful completion of the run-in period.

Exclusion: Presenting for their pre-surgical consultation less than 4 weeks before surgery; Severe cardio-respiratory disease (For operationalizing: ASA 4/NYHA 4); Substance use disorder based on DSM-V criteria; Allergy or intolerance to cannabis, cannabis derivatives, or other ingredients of the study drug; Patients with a chronic pain condition affecting the knee (other than osteoarthritis) (e.g.: patients with knee pain due to fibromyalgia or chronic pain syndrome will be excluded); Patients who are pregnant, planning to be pregnant, or breastfeeding; Revision TKA; Bilateral TKA; Unwilling or unable to follow the study protocol.

ClinicalTrials.gov NCT03825965