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.”