No one likes joint injections, least of all in an already painful joint. But it is important to realize that injections can be very effective treatments for arthritis. Whether you have rheumatoid arthritis (RA), osteoarthritis (OA), gout, or bursitis, injections can reduce swelling and pain and improve joint mobility.
What are the risks and side effects? Of the risks that come with corticosteroid injections, the most feared is an infection in the joint. Fortunately, the risk of infection is extremely low. Other side effects of corticosteroid injections include flushing of the face, which is common but usually doesn’t last long. Shrinkage (atrophy) or discoloration of the skin at the injection site can also occur. In some cases, a person may have an allergic reaction to something in the injection. Some people have a temporary flare of arthritis in the injected joint that begins a few hours after the injection and lasts a couple of days. (An infection, on the other hand, wouldn’t show any symptoms until several days after the injection.) The flare can be treated with ice and pain-relieving drugs.
People whose joint pain is caused by an infection — a condition called septic arthritis — should not get a corticosteroid injection. (Septic arthritis is treated with antibiotics and draining of the joint.) In fact, an active infection anywhere in the body would be a signal not to get a corticosteroid injection.
People with poorly controlled diabetes should also avoid corticosteroid injections, as the corticosteroids increase the risk of raising already high blood glucose levels. Even people with well controlled diabetes should still monitor and manage their blood sugars carefully after an injection, as it may take a few days for their blood sugar levels to assimilate to their pre-injection patterns. People who have been diagnosed with bone thinning (osteoporosis) in the bones surrounding a joint may choose to use these injections carefully as well, because long term use can further weaken bone. Corticosteroid injections are not given into a replacement joint.
Doctors are usually cautious about giving a corticosteroid injection to someone taking a blood-thinning medicine such as warfarin (Coumadin) or heparin because of the risk of bleeding. If you take one of these drugs, your doctor may test your blood before giving you an injection to make sure you are not at too great a risk of bleeding.
There are a few conditions that should not be treated with a corticosteroid injection. These include Achilles tendinitis or tendinitis in the knee cap (patellar tendon), as these tendons are at risk of being weakened by the corticosteroid drug.
How long do corticosteroid injections last? It depends what problem is being treated. The answer depends on several factors and differs from person to person. In some cases, one injection may resolve the issue permanently. Other times, the benefit of the injection may last only a month or two.
If the pain relief of a corticosteroid injection wears off after a short time, you may need to wait awhile before you have another one. The standard recommendation is that corticosteroid injections should not be given into the same joint more than four times within a year, or every three months if done on an ongoing basis. The concern is that repeated corticosteroid injections could degrade cartilage and weaken tendons or ligaments in the joint. There is also a possibility that too much corticosteroid could get into the bloodstream, which might bring about the same side effects as oral corticosteroids: thinning bones, increased blood glucose, and weight gain. With local injections, however, the risk of these bodywide side effects is thought to be low.