Medical Cannabis Provides Only Minor Relief for Chronic Pain

By Pat Anson, PNN Editor

An international team of researchers has concluded that medical cannabis and cannabinoids do not provide relief to most people with chronic pain, but are of some benefit to others.

The findings, based on a limited review of 32 medical cannabis studies, were published in the journal BMJ. They are the third set of international guidelines released this year to discourage the use of cannabis as an analgesic because clinical evidence is lacking.

“We are hopeful that patients and physicians will find our guideline helpful, and take away that while medical cannabis will not be effective for most people living with chronic pain, it may provide important benefits for a minority of patients,” said lead author Jason Busse, associate director of McMaster University’s Medicinal Cannabis Research Center in Ontario, Canada.

“For example, we found that 10% more patients that used medical cannabis vs. placebo in trials reported an important improvement in pain relief. This means that only one patient of every 10 treated with medical cannabis experienced this improvement.”

Busse and his colleagues said medical cannabis might provide a “small increase” in pain relief, sleep quality and physical function, with a “small to very small increase” in side effects such as dizziness, nausea and cognitive impairment.

It’s important to note that the panel’s recommendations do not apply patients in palliative care or to smoked or vaporized cannabis. The research team, which included a diverse group of physicians, academics and patient representatives, could not find a good quality clinical study that explored the use of inhaled cannabis.

“We hope that such trials will be forthcoming, as cross-sectional data has found many (perhaps the majority of) people living with chronic pain who use cannabis therapeutically use dried flower products that are typically inhaled or vaporized,” Busse told PNN in an email.

“The most robust evidence base is probably for use of cannabidiol (CBD) to help manage certain forms of pediatric epilepsy; however, most patients use cannabis to manage chronic pain and there are important evidence gaps that urgently need to be addressed so that patients can make fully-informed decisions.”

Due to the limited research on inhaled cannabis, the guideline’s recommendations only cover cannabis products such as edibles, sprays, oils and tinctures, which are usually low in tetrahydrocannabinol (THC), the psychoactive ingredient in cannabis that makes people high.

The panel recommended that non-inhaled cannabis or CBD only be used on a trial basis by patients when “standard care” for pain management is not sufficient. The recommendation applies to adults and children with moderate to severe chronic pain caused by cancer, neuropathy, nociceptive pain or nociplastic pain. The latter two categories cover conditions such as osteoarthritis and fibromyalgia.

“Our weak recommendation in favour of a trial of medical cannabis or cannabinoids reflects a high value placed on small to very small improvements in self reported pain intensity, physical functioning, and sleep quality, and a willingness to accept a very small to modest risk of mostly self limited and transient harms,” researchers said.

“The panel, including patient partners, believes that there is great variability in how much reduction in pain severity, improvement in physical functioning, or sleep quality each patient would consider important. Patients who place a high value in improving these symptoms by any amount are more likely to pursue a trial of medical cannabis or cannabinoids.”

The researchers recommend that patients start with a low-dose CBD product, and gradually increase the dose and THC level depending on how the patient responds.

Two medical guidelines released earlier this year also take a dim view of cannabis as a pain reliever. The Australian and New Zealand College of Anaesthetists (ANZCA) urged doctors not to prescribe medical cannabis for patients with chronic pain unless they are enrolled in a clinical trial.

The International Association for the Study of Pain also said it could not endorse the use of cannabinoids to treat pain because there was not enough evidence on the safety and efficacy of CBD.

Study Questions Value of Knee Replacement Surgery

By Pat Anson, Editor

New research is raising questions about the value of knee replacement surgeries, one of the fastest growing elective procedures in the United States.

In an analysis of over 7,400 patients with osteoarthritis who had knee replacement surgeries, researchers concluded the procedure often had minimal effects on quality of life and wasn’t worth the cost. But when the surgeries are performed on patients with more severe knee pain, their effectiveness increases, researchers reported in The BMJ.

The annual rate of total knee replacements in the U.S. has doubled since 2000, with more than 640,000 surgeries now performed annually at a cost of $10.2 billion.

"Given its limited effectiveness in individuals with less severely affected physical function, performance of total knee replacement in these patients seems to be economically unjustifiable," wrote lead author Bart Ferket, MD, an assistant professor at the Icahn School of Medicine at Mount Sinai in New York City.

"Considerable cost savings could be made by limiting eligibility to patients with more symptomatic knee osteoarthritis,"

Osteoarthritis is a joint disorder that leads to thinning of cartilage and progressive joint damage. Nearly 40 percent of Americans over the age of 45 have some degree of knee osteoarthritis, and those numbers are expected to grow as the population ages.

Ferket and his colleagues found that about a third of the patients who had their knees replaced continued to experience chronic pain after the procedure. Their quality of life generally improved, but the change was small. The improvement in quality of life was higher when patients with lower physical scores before surgery were operated on.

“The practice of total knee replacement as performed in a recent U.S. cohort of patients with knee osteoarthritis had minimal effects on quality of life. If the procedure were restricted to patients with more severe functional status, however, its effectiveness would rise, with practice becoming economically more attractive,” they concluded.

"Our findings emphasize the need for more research comparing total knee replacement with less expensive, more conservative interventions, particularly in patients with less severe symptoms.”

Previous studies have also questioned the value of many knee surgeries. A five year study of 175 knee replacement patients by the National Institutes of Health found that over a third of the surgeries were inappropriate. Many patients had pain and other symptoms that were too mild to justify having their knees replaced.  

Another study found that arthroscopic knee surgery is “not an economically attractive treatment option” compared to physical therapy, exercise and medication.

In arthroscopic surgery, a doctor makes a small incision in the knee and inserts a tiny camera and instruments to repair damaged ligaments or torn meniscus. Arthroscopic surgery is far less invasive than a total knee replacement. Depending on insurance, hospital charges and the surgeon, arthroscopic surgeries cost about $4,000.  A total knee replacement costs about $28,000 according to HealthCare Bluebook.