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A new study raises concerns about steroid injections for knee osteoarthritis. Luis Alvarez/Getty Images
  • Researchers say corticosteroid injections may actually make knee osteoarthritis worse for many people.
  • They add that hyaluronic acid injections don’t appear to cause the same deterioration.
  • Experts say the research provides important information for people with knee osteoarthritis as well as the medical professionals treating them.

Osteoarthritis, the most common form of arthritis, affects more than 32 million adults in the United States, according to the Centers for Disease Control and Prevention (CDC).

Sometimes called degenerative joint disease, “wear and tear” arthritis, or just “OA”, the condition occurs most often in the hands, hips, and knees.

Knee osteoarthritis, specifically, is a chronic, degenerative and progressive condition that affects at least 19% of American adults aged 45 years and older, a rate that has doubled since the mid-1900s.

More than 10% of people with knee osteoarthritis seek noninvasive treatment for pain relief through corticosteroid or hyaluronic acid injections.

However, two new studies comparing injections commonly used to relieve the pain of knee osteoarthritis report that corticosteroid injections may actually worsen knee arthritis.

The results of both studies were presented today at the annual meeting of the Radiological Society of North America.

Neither study has been published in a peer-reviewed journal yet.

Researchers in both studies chose cohorts from the Osteoarthritis Initiative, a study of nearly 5,000 participants with knee osteoarthritis currently in its 14th year of follow-up.

In the first study, researchers at the University of California, San Francisco included 210 Osteoarthritis Initiative participants, 70 of whom received intraarticular injections with a control group of 140 who did not receive injections during a two-year period.

Of the 70 people who received injections, 44 were injected with corticosteroids and 26 were injected with hyaluronic acid.

An MRI was performed on all of the people in the study at the time of the injection and two years before and after.

Dr. Upasana Upadhyay Bharadwaj, a research fellow in the Department of Radiology at the University of California San Francisco, told Healthline that this study is the first direct comparison of corticosteroid and hyaluronic acid injections using the semi-quantitative, whole-organ assessment of the knee with an MRI.

“There have been some studies but most are focused on X-rays. MRI shows more detail and helps us look at the changes that take place,” she said.

“The MRIs showed the faster progression in terms of cartilage and other structures compared to controls. Like graying hair, these changes happen, but some people feel pain more than others,” she added.

Bharadwaj noted that corticosteroid knee injections were significantly associated with the overall progression of osteoarthritis in the knee, specifically in the lateral meniscus, lateral cartilage, and medial cartilage.

Hyaluronic acid knee injections, however, were not significantly associated with the progression of osteoarthritis in the knee. In fact, when compared to the control group, hyaluronic acid injections were actually associated with decreased progression of knee osteoarthritis.

Bharadwaj said that while both corticosteroid and hyaluronic acid injections are reported to help with symptomatic pain relief for knee osteoarthritis, their results conclusively show that corticosteroids are associated with significant progression of knee osteoarthritis up to two years post-injection and must be administered with caution.

Hyaluronic acid, on the other hand, may slow down the progression of knee osteoarthritis and alleviate long-term effects while offering symptomatic relief, she said.

In the second study, researchers at the Chicago Medical School of Rosalind Franklin University of Medicine and Science compared the radiographic progression of osteoarthritis in people who received injections of corticosteroids and hyaluronic acid.

Researcher and medical student Azad Darbandi’s team selected a cohort of 150 people with similar baseline characteristics from the Osteoarthritis Initiative database.

Over a 36-month time period, 50 people received corticosteroid injections, 50 received hyaluronic acid injections, and 50 people received no injections. X-rays of the knee were done at baseline and 2 years later.

Compared to those who received an injection of hyaluronic acid or no treatment at all, people injected with corticosteroids had significantly more osteoarthritis progression, including medial joint space narrowing, a hallmark of the disease, Darbandi said in a statement.

“The results suggest that hyaluronic acid injections should be further explored for the management of knee osteoarthritis symptoms and that steroid injections should be utilized with more caution,” Darbani said.

Luca Maria Sconfienza, Ph.D., a professor of radiology at the University of Milano in Italy was not part of either study.

He told Healthline that these studies provide important information for people with knee osteoarthritis.

“They can be effective in reducing pain inflammation. However, steroids may damage cartilage further and bone,” he said. “I think this study provides important information. It further confirms what many people have already thought.”

Bharadwaj concluded that being aware of the long-term effects of these injections will help people with osteoarthritis and clinicians make more informed decisions.

“At this point, the study is for patients to help make informed choices, and what happens next is that the research should follow up with more controlled studies to get more information,” she said.