Nov. 30, 2022 – A pair of new studies suggest that steroid injections may worsen arthritis of the knee, a condition that affects more than 32 million adults in the United States.
The studies also found that knee injections of a lubricant called hyaluronic acid may help protect the joint.
“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,” researcher Azad Darbandi, a student at Chicago Medical School of Rosalind Franklin University of Medicine and Science, said in a news release.
Hyaluronic acid is a natural gel-like substance in the body, especially found in the eyes, joints, and skin. It can also be produced in laboratories from bacteria or by using rooster combs, the fleshy crown on a rooster's head, according to the Cleveland Clinic.
It’s a common treatment for arthritis, which is medically referred to as osteoarthritis. Arthritis usually affects the hands, knees, hips, and spine by permanently wearing down cartilage that cushions the ends of the bones in those joints, the Mayo Clinic says.
Another common arthritis treatment is corticosteroids, commonly just referred to as steroids. They help reduce inflammation and are a synthetic version of cortisol, which the body makes naturally.
The first study was done by researchers at the University of California in San Francisco who examined data for 210 people previously diagnosed with knee arthritis. The people in the study were split into three groups: 44 patients got corticosteroid knee injections, 26 got hyaluronic acid injections, and 140 control group patients did not receive injections during a 2-year period. MRIs were compared from before the injection and 2 years later to measure changes in the knee joint.
Arthritis got worse significantly in the patients who got steroid injections, while the hyaluronic acid group showed less disease than the patients who had no treatment at all.
The second study was led by researchers at the Chicago Medical School of Rosalind Franklin University of Medicine and Science. They examined data for 150 patients with similar levels of knee arthritis. Of them, 50 got steroid injections, 50 got hyaluronic acid injections, and 50 were not injected during a 3-year period. Researchers compared X-ray knee images at the start of the study and 2 years later.
The steroid injection group’s arthritis worsened more than that of the other two groups, the researchers found.
But some experts told NBC News the studies have hefty limitations. For instance, because so many other things can influence the progression of arthritis, it’s tough to tell if the steroid injections caused the condition to get worse, said New York rheumatologist Jonathan Samuels, MD.
“We don’t have the biology to prove that the injection itself is causing accelerated damage. It’s hard to connect the dots from injection to damage from this preliminary data,” he said. “But it’s an important question, because it’s such a common practice to be injected with steroids.”