Learn About Your Knee Pain

What Cortisone Shots Actually Do for Knee Pain

A cortisone shot places a corticosteroid directly into the knee joint. Doctors often mix it with a numbing medicine to ease the sting. The steroid calms your immune system’s inflammatory response, which lowers swelling and eases pain, often within a few days.

What cortisone does not do is rebuild worn cartilage or repair damage inside the joint. It quiets the fire alarm. It does not put out the fire.

Why the Relief Doesn’t Last

In knee osteoarthritis, the joint tissue breaks down over time. A cortisone shot can quiet pain signals for a while, but it does not stop this breakdown. Most patients feel relief fade within 6 to 12 weeks, as the drug wears off and the underlying joint condition remains.^[1]

Newer research points to another piece of the puzzle: hypervascularity. This means tiny, abnormal blood vessels grow inside the joint lining. These vessels carry new nerve endings that are especially sensitive to pain. Cortisone does not remove these vessels, which is one reason shots stop working for some patients even when inflammation seems well controlled.

How Many Cortisone Shots Can You Get in Your Knee?

Most doctors limit cortisone shots to about 3 to 4 per year in the same knee, spaced several weeks apart.^[2] This spacing gives joint tissue time to recover between injections.

Repeated shots have been linked to faster cartilage thinning in some studies. If your relief keeps getting shorter with each shot, or stops working altogether, that pattern is worth discussing with a knee specialist rather than simply requesting another injection.

Cortisone Shot Side Effects to Know

Along with fading relief, cortisone shots carry some other risks worth knowing about, including:

• Steroid flare: a short burst of extra pain and swelling for about 48 hours after the shot.
• Skin changes: thinning or lightening of the skin near the injection site.
• Blood sugar changes: a notable concern if you have diabetes.
• Infection risk: every needle into the joint space carries a small but real risk of infection.

If side effects or fading relief have you looking for other paths, you can explore treatment options beyond repeated injections.

What Is the Success Rate of Cortisone Knee Injections?

There is no single number that applies to everyone. Success depends on how advanced your knee osteoarthritis is and what result you are hoping for. Many patients get real, short-term relief from a cortisone shot. People with more advanced joint wear tend to respond less well, and relief tends to be shorter each time a shot is repeated.^[1][2]

If your shots are giving you less relief each time, that trend itself is meaningful information, even without one exact percentage attached to it.

What Happens If a Cortisone Shot Doesn’t Work?

A shot that doesn’t work doesn’t always mean the wrong treatment was chosen. Sometimes it’s a sign that your pain is coming mostly from structural wear rather than active inflammation. Cortisone can only help with the second kind.

If this happens to you, it helps to track a few details before your next appointment: how your pain changes with rest versus activity, when relief faded after your last shot, and how many shots you’ve had so far. This pattern helps a specialist figure out what’s really driving your knee pain.

What Is the Next Step If a Cortisone Shot Doesn’t Work?

If cortisone keeps falling short, it’s worth talking with a knee pain specialist about what’s actually causing your pain to persist.

USA Pain Center offers genicular artery embolization (GAE), a minimally invasive, image-guided procedure that helps ease knee pain by targeting abnormal blood vessels linked to chronic joint inflammation. To find out if GAE is right for your condition, schedule a specialist evaluation, and explore our side-by-side comparison of GAE vs. cortisone shots to see how the treatments differ.