PROCEDURE: Knee Injection
NOTE: THESE PROCEDURES OR INJECTIONS SHOULD ONLY BE ADMINISTERED BY AN MD OR DO TRAINED IN INTERVENTIONAL PAIN MEDICINE
Knee Injections are given by a needle directly into the knee joint. There are two types of injections used to treat symptoms of knee osteoarthritis: joint lubricants (viscosupplementation) and cortisone (steroid injection).
Joint Lubricants (Viscosupplementation) Articular cartilage is the smooth coating covering the surface of the bones inside the knee. It helps to lubricate and cushion the surfaces of the knee joint. In osteoarthritis, this coating is damaged leading to reduced lubrication and cushioning. This results in some of the pain, grinding, and other symptoms experienced by osteoarthritis-sufferers.
Viscosupplementation therapy involves injecting a clear gel-like substance directly into the knee joint. These injections help to restore some of the lubrication lost by damaged cartilage and thus improve symptoms. An injection is given as one shot into the knee joint each week for three-six weeks. Usually people who respond to this form of treatment will experience some improvement for six to ten months. An injection series can be repeated every six months as needed. This method of therapy is used for people who have not benefited from less invasive therapies such as lifestyle modification, physiotherapy, and oral medications. The injections do carry a small risk of infection or allergic reaction to the lubricant itself. Physician can provide additional information about the risks and benefits of this procedure.
Injectable Cortisone Physician can inject a powerful anti-inflammatory drug called cortisone (or corticosteroid) directly into the joint. Cortisone injections are reserved for people with a severely inflamed knee with uncontrolled pain. Cortisone injection can provide rapid relief from a tender, swollen osteoarthritic knee which has failed to respond to other forms of treatment. The benefit of an injection may last anywhere from a few days to more than 6 months. Injections may be less effective with each successive injection.
It should be noted that although cortisone is a steroid, it differs from the performance enhancing steroids used by some athletes and discussed in the media. Injectable cortisone does not have the side effects associated with such steroids. There are however some risks associated with cortisone injection. Repeated injections may promote the breakdown of articular cartilage, which is the cause of osteoarthritis in the first place. For this reason, multiple injections are not usually recommended. There is also a small risk of infection or allergic reaction to the steroid preparation. Some patients may experience a “steroid flare” in which the joint becomes more inflamed for 2-3 days following injection. Anti-inflammatory medications and/or ice may prevent or control this reaction.
What is an Intra-Articular Joint Injection? Injections into joints (ie. hip, shoulder, wrist) are intra-articular injections. If you have a swollen or painful joint your doctor may inject a steroid medication into the joint. Sometimes your doctor may inject a local anesthetic (numbing medicine) along with the steroid.
Why Should I have an intra-articular steroid injection? The steroid injection is given to decrease pain and swelling in the joint.
How long does it take the steroid injection to work and how long will it last? It varies between people; improvement usually starts within 1 to 2 days. If helpful, the injection usually lasts from a few weeks to several months.
What is injected into my joint? The steroid medications are related to cortisone, which is produced by the body itself. The purpose of the injection is to calm down the excessive inflammatory process that may be going on because of injury, excess use, or similar problems. Cortisone injections can also be used for diagnosing some conditions, such as carpal tunnel syndrome, wrist ligament tears, etc. The form of cortisone that I use is called triamcinolone acetonide. It has the longest duration of action and the greatest potency of the cortisones. The most likely side effect is decrease of skin pigmentation in a region about the size of a dime or a quarter. This is not permanent, but may last up to a year.
Are there any side effects? Side effects are very unlikely. Occasionally, the joint is worse for the first 24 hours after the injection. After that the joint normally settles. If the joint becomes more painful after this, please call 718 687 2010 as this could be a sign of infection (a very rare complication). A large number of injections into the same joint may cause damage to the joint.
How do I do it painlessly? I put fast acting numbing medicine in the shot. What is it? Lidocaine (a numbing medicine) that I have specially buffered (made the pH the same as the body’s) to take all of the sting out of it and to speed up how fast it works. The Lidocaine usually is effective in one to two seconds. Amazing, right? This way, you do not feel the long acting numbing medicine or the steroid medicine, which is actually the medicine that does the job.
How many injections can I have? There is no firm limit to the number of injections. However, the effect tends to decrease with repeated injections. There could also be problems from a large number of injections into the same joint.
How often can I have an injection? There is no firm rule about this, but your doctor will want to avoid repeating the injection more often than is necessary.
Do I need to do anything myself after the injection? You should rest the joint after the injection for the first 24-48 hours, especially after the knee or ankle has been injected.