Use of Corticosteroids in Osteoarthritis
Corticosteroid injections can improve pain in some people with OA.
Osteoarthritis (OA) is one of the most common forms of arthritis. The joint pain and stiffness caused by OA can make it difficult to work, play sports and perform daily activities. Anti-inflammatory and analgesic medications may help ease your pain. Your doctor may also recommend physical therapy. If these conservative measures don’t work, it may be time for a corticosteroid injection directly into your aching joint.
Corticosteroids are medications that mimic the effects of the hormone cortisol, which is produced naturally by the adrenal glands. Cortisol affects many parts of the body, including the immune system. It helps lower levels of prostaglandins and downplays the interaction between certain white blood cells (T-cells and B-cells) involved in the immune response. Corticosteroids stimulate this effect to control inflammation.
Not for Everyone
“While the injections help some patients significantly, at least for a period of time, others do not get much relief at all,” says Jonathan Samuels, MD, assistant professor of rheumatology at New York University Langone Center for Musculoskeletal Care, New York City.
The purpose of the injection is to reduce the irritation caused by bone interacting with bone – which is what happens when the smooth, cartilage interface wears away. Dr. Samuels says there can be several reasons why these direct “steroid shots” sometimes don’t work.
“Some patients’ disease is too far advanced to respond to this approach, and in difficult and bulky knees it may be hard to locate the actual joint space,” Dr. Samuels says. That can result in the medication delivered to the wrong place. Ultrasound guidance, he says, can help put the corticosteroid where it needs to be.
In fact, researchers at the University of North Carolina School of Medicine found ultrasound guidance dramatically improved the accuracy of needle placement in one of the most common joints affected by OA, the knee. Their research showed an ultrasound accuracy of about 96 percent, versus about 78 percent for injections guided simply by anatomy.
No doubt, some patients feel remarkably better after a steroid shot. But Dr. Samuels says it is never the only answer to their pain. “Any candidate for a steroid injection should still receive physical therapy, supportive bracing and oral or topical medication to maximize the response to the injection.”
How Long Will it Last?
Relief from the injections generally does not last forever. Guidelines by American Family Physician put the duration of pain relief at no more than two months. Researchers at Washington University School of Medicine in St. Louis, Mo., pegged steroid shot therapy as “a short-term treatment of a chronic problem.”
Factors such as extent of inflammation and overall patient health can determine how long a steroid shot will last. But Roy Altman, MD, professor of medicine, rheumatology, at UCLA Medical Center, Los Angeles, says with an acute inflammation, single injections can provide very long-term relief – for a year or longer. “It’s so variable. It’s almost like patient selection makes a difference."
But no matter the duration of relief, patients should never be given an unlimited number of injections. “In general, a patient shouldn’t have corticosteroid injections into any given joint more than once every three to four months,” says Dr. Samuels. “Too many injections increase the risk of side effects, such as avascular necrosis, which is the lack of blood flow to a part of the bone that causes it to collapse.”
“If you did no greater than four injections a year in a given joint, it’s pretty safe,” Dr. Altman says. He does note, however, that repeat injections tend to be less effective.
Effects of Corticosteroid Injections
Other possible side effects from corticosteroid injections include nerve damage and thinning of nearby bone.
Because the injections are formulated as slow-release crystals, patients can, in the short term develop irritation in the joint similar to gout. “It’s usually not very severe,” Dr. Altman says of these so-called ‘crystal flares.’ Icing the joint helps, he says.
Another possible complication is infection. But Dr. Altman says that’s extremely rare – provided a reasonable aseptic technique is used. “I’ve been doing corticosteroid injections since 1967 and I have seen one infection in all this time,” he says.
Researchers in Germany recently looked at nearly 300 cases in which complications occurred after local corticosteroid injections and found that in some instances, lack of aseptic technique was a contributing factor. They also noted that too many injections in a compressed amount of time increases the risk of infection.
That said, some patients do safely get multiple injections at the same time. “Both knees can be injected, for example, at the same visit,” says Dr. Samuels. “And there is no absolute limit to the number of joints that can be injected. But we rarely inject more than two to three at one visit.”
Why Only Injections?
Some patients with osteoarthritis may wonder why oral corticosteroids, such as prednisone, aren’t used instead of a local injection – especially since they can work so well with rheumatoid arthritis. Dr. Samuels says it’s because the two diseases are two different animals.
“Osteoarthritis is not a systemic – that is, whole body – condition, such as rheumatoid arthritis,” he says. “Because osteoarthritis is localized to particular joints – and with less joint lining inflammation, we wouldn’t expect a successful anti-inflammatory response using oral corticosteroids.”
Plus, oral steroid use is associated with numerous side effects, including changes in blood sugar and bone density.
The American College of Rheumatology (ACR) has published updated guidelines for treating osteoarthritis in pharmacological and non-pharmacological ways. And while the group conditionally endorsed the use of corticosteroid injections for hip and knee osteoarthritis – after other, more conservative treatments had failed – it recommended against using the therapy in osteoarthritis of the hands.
Dr. Altman says the ACR guidelines are based on available literature. But his experience with corticosteroid injections to joints in the hand has been different: “Personally, with good patient selection, these injections are wonderful.”