Steroid shots offer pain relief from knee arthritis, but they may make the condition worse over time

New research suggests hyaluronic acid shots may be a safer choice for the millions of Americans who suffer from the degenerative disease

More than 10% of patients with knee osteoarthritis seek noninvasive treatment for pain relief through corticosteroid or hyaluronic acid injections.
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Many people suffering from knee osteoarthritis turn to corticosteroid injections for pain relief, but two new studies suggest that the treatment may be do more harm than good.

The studies found that people experienced temporary pain relief after receiving the shots, but their knee arthritis appeared to progress more rapidly than it did in people who received injections of hyaluronic acid instead. 

Osteoarthritis is the most common form of arthritis, affecting 32.5 million adults in the U.S. About 14 million people in the U.S. have been diagnosed with knee arthritis in the past 20 years. And more than 10% of patients seek noninvasive treatment for pain relief through corticosteroid or hyaluronic acid injections.

"While both corticosteroid and hyaluronic acid injections are reported to help with symptomatic pain relief for knee osteoarthritis, our 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," said Dr. Upasana Upadhyay Bharadwaj, a research fellow at University of California, San Francisco.

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

The studies' findings were presented at the annual meeting of the Radiological Society of North America in Chicago. The research is considered preliminary until it is published in a peer-reviewed journal.

Previous research on the effectiveness of corticosteroid shots in the hips and knees has been mixed. Some, including a 2019 study, have found the shots can accelerate damage and the need for joint replacements. But others have found that disease progression is similar between those who get steroid injections and those who choose hyaluronic acid injections instead.

Dr. Jonathan Samuels, a rheumatologist at NYU Langone Health in New York City, who was not involved in either study, told U.S. News & World Report that the studies raise important questions, but that there is not enough evidence to prove steroid injections accelerate arthritis progression. 

There are many factors that influence the progression of the disease including obesity, knee injury and physical activity, he said. 

Patients need to discuss all the risks and benefits of these injections with their doctor so they can make an informed decision, experts say.

In the University of California, San Francisco study, researchers used MRI scans to compare osteoarthritis progress in 210 patients who either received no injection, corticosteroid injections or hyaluronic acid injections.

Each of the participants received an MRI scan of their knee two years before the injection, at the time of the injection and two years after. The researchers evaluated diseases progression using a grading system that focuses on the meniscus, bone marrow lesions, cartilage, swollen joints and ligaments. 

In the group who received the corticosteroid injections, the scans showed an overall progression of osteoarthritis in the knee, especially in the lateral meniscus, lateral cartilage and medial cartilage. Compared to the group who didn't receive any injections, those who were injected with hyaluronic injection had much slower disease progression, particularly in bone marrow lesions.

The second study, conducted by researchers at Rosalind Franklin University of Medicine and Science in North Chicago, Illinois, compared X-rays given to 150 patients who either received corticosteroid injections, hyaluronic shots or no injections. 

The researchers focused their analysis on joint space narrowing, the formation of bone spurs and bone thickening around the knee cartilage. Overall, the patients who received corticosteroid injections had more disease progression, including medial joint space narrowing when compared to the other two groups.

"Even though imaging findings for all patients were similar at baseline, the imaging hallmarks of osteoarthritis were worse two years later in patients who received corticosteroid injections compared to patients who received hyaluronic acid injections or no treatment at all," said researcher Azad Darbandi, a medical student at Rosalind Franklin University of Medicine.

"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."