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A common treatment for a chronic pain condition that affects millions of Canadians may not be as safe as once thought, and experts say a growing body of research shows it could be doing more harm than good.

Osteoarthritis is a painful progressive disease of the joints that affects over five million Canadians, according to the Arthritis Society, more than all other forms of arthritis combined .

Corticosteroids are often injected directly into the joint tissue for pain relief, but experts are calling into question the efficacy and safety of this treatment.

"This is really an eye-opener," says Dr. Ali Guermazi, a professor of radiology at Boston University and the lead author of a new observational study published in the journal Radiology this week.

Guermazi and his team studied 459 patients at the Boston Medical Center who received hip or knee injections of steroids last year. What they found were four types of complications affecting eight per cent of patients after the injections.

Six per cent saw accelerated progression of osteoarthritis, 0.9 per cent had stress fractures develop on the bone, 0.7 per cent suffered osteonecrosis, or what Guermazi calls "the death of the joint"; and a further 0.7 per cent saw "rapid joint destruction" including bone loss.

When asked if health practitioners should be rethinking the treatment altogether, Guermazi said it's "ultimately what should be done."

"This is an observational study. So it needs to be followed by studies that are strong, and robust … to try to make sure that causality exists 100 per cent, even though we think that it's probably there," he said.

"We need that confirmation. As soon as we have that, I do think, ultimately 100 per cent we need to look at this very seriously.

"We need actually to decide that this drug is not as safe as we thought."

Growing body of research

Guermazi points to several studies with similar findings published in the past few years.

A groundbreaking study published in JAMA in 2017 conducted a double-blind randomized clinical trial that injected steroids into half of a group of osteoarthritis knee patients and a placebo of saline into the others. It concluded there was "no significant difference in knee pain."

What they did find was a narrowing of the joint space and "cartilage volume loss" in patients that received steroid injections, which Guermazi says is something his study found as well.

A study published in Skeletal Radiology this year looked at 70 patients who received steroid injections in their hips and found they were more likely to have osteoarthritis progression (44 per cent) and osteonecrosis (17 per cent).

A Cochrane Musculoskeletal review in 2015 collected data from 27 trials on knee osteoarthritis patients worldwide and found it was "unclear" if there were actually any benefits to the treatment.

Current and future impact on Canada

The challenge of osteoarthritis is that it has no cure, with treatments instead focused on pain management and symptom control.

It's also costly for the health care system, and with an aging Canadian population the prevalence of the disease could skyrocket.

"The costs of osteoarthritis amount to about $10 billion in direct costs every year," says Siân Bevan, chief science officer of the Arthritis Society.

"When you look at some of the indirect costs, that number is estimated to be about $17 billion — so huge numbers in terms of the impact."

Bevan said arthritis is also the No. 1 cause of joint replacement in Canada, covering 80 per cent of hip replacements and 99 per cent of knee replacements, further adding to the cost.

"When you look at the projections around arthritis, we know that we will be seeing a significant increase in the number of people affected," she said.

"So if that number is six million Canadians today, where that's with all types of arthritis, we're projecting that number to be nine million Canadians by 2040. So that's a 50 per cent increase."

Bevan said Guermazi's study builds on other research with similar views on corticosteroid injections, but she says the challenge is that there is a lack of "high quality evidence" on the treatment.

"There's some uncertainty about some of the studies that have come out. There are some studies that have shown benefits, but then some questions around whether those are actually meaningful benefits in particular in the long term," she said.

"Our position is certainly consistent with what we're seeing represented in this current study, which is that these injections might be helpful for some people with arthritis. But it's not completely clear."

Bevan said the injections should be looked at as a "potential option" in the short term if other treatments have failed, but not as a long-term treatment.

"All of these studies are important because there's a question around potential benefit," she said.

"But there's also a question around risks related to these kinds of procedures. So those are all really important pieces of information for physicians and patients to understand."

Alternative treatment options

So what other treatment options exist?

"We do not have any approved drug, whether it's in Canada or around the world — there is no drug which can modify the disease," says Dr. Mohit Kapoor, director of arthritis research at the University Health Network in Toronto.

"What is available are drugs which are going to mask the symptoms."

Nonsteroidal anti-inflammatory drugs and other types of painkillers can mask pain and inflammation but don't do anything to the underlying disease, he said.

"There is one treatment which is effective, and it's not actually a drug treatment, it's really to lose weight," said Guermazi, referencing another JAMA study that looked at exercise as a solution.

"So you decrease your pain, you decrease your stiffness ... it goes without saying that's the only treatment that is there."

Weight loss is the only other known treatment for osteoarthritis, Dr. Ali Guermazi says. (iStock/Getty Images)

Kapoor said one effective exercise program developed in Denmark, called the GLA:D program , has recently been implemented in Canada with positive results.

A 2017 report on the effectiveness of the program in Canada showed a 28 per cent reduction in pain intensity, as well as 35 per cent of participants with increased physical activity.

Kapoor said in 2016 his team at UHN identified two molecules that are present at a higher level in the joints of patients who have an advanced stage of the disease.

"One of these molecules is so detrimental, that once the level of this molecule is increased in the cartilage of patients with knee or spine osteoarthritis, it basically eats up the cartilage," he said.

Once the molecules were identified, Kapoor said researchers at UHN developed a "molecule blocker" that can be injected into the joint, much like a corticosteroid injection, to stop their activity.

"In animal studies, we have seen significant reduction in the rate with which your cartilage degenerates," he said. His team hopes to determine if the drug is safe for use on humans.

"If it's safe, we would like to then initiate a clinical trial with the hope that this injection can stop the disease process and provide us the disease modification effect we all are looking for to be able to treat osteoarthritis."

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