Osteoarthritis Health Center

Injectable Medications for Knee Osteoarthritis

If you have knee osteoarthritis, doctors can offer a variety of treatments to relieve your symptoms. One option is to inject medication into your knee.

There are different types of injections, and they're an important part of treating knee osteoarthritis for many people, says Roy Altman, MD, an osteoarthritis expert at UCLA. Injections can be especially helpful for people who haven’t gotten relief from NSAIDs like ibuprofen, or people who can’t take those drugs due to side effects.

Osteoarthritis (OA) is a common form of arthritis that often affects the knees. It develops when the cartilage -- the smooth covering that protects the bones in the joint -- breaks down. The surface of the bones becomes damaged, causing pain, swelling, stiffness, and disability.

How Knee Injections Work

First, your doctor will give you a shot of anesthetic to numb your knee.  

Next, your doctor may use a needle to draw out any extra fluid that's in your knee.

After that, you'll get the pain-relieving injection, usually just below your kneecap. The shot shouldn't hurt, and the drug will work throughout the joint, says John Richmond, MD, an orthopedic surgeon at the New England Baptist Hospital in Boston.  

Different treatments have side effects that you should discuss with your doctor beforehand. The two most common types of knee injection for OA are corticosteroids and hyaluronic acid.

Reduce Inflammation With Steroids

Corticosteroid injections are useful for treating flare-ups of OA pain and swelling with fluid buildup in the knee, Richmond says.

These injections help relieve symptoms by reducing inflammation in the joint. But they’re not a perfect solution in every case. If you're considering this treatment, keep this in mind:

They work quickly. These injections offer “very rapid” relief, usually within 24 to 48 hours, Richmond says.

The benefit is short-term. On average, the pain relief lasts from 6 to12 weeks, Richmond says. Often, that’s long enough to get you through a flare-up of osteoarthritis until your symptoms subside.

You shouldn’t use them frequently. A corticosteroid shot often works best the first time, Altman says. After that, they tend to give less relief.

In most cases, Richmond tells his patients they can use these shots two to three times a year. Using them too often may damage cells in the knee that make cartilage.

Hyaluronic Acid

Most of the fluid in a healthy knee is hyaluronic acid, Altman says. But when you have knee OA, the hyaluronic acid in your knee thins. Your doctor can inject more hyaluronic acid into your knee to boost the supply.

Studies have shown that hyaluronic acid injections may help more than pain-relief medications for some people with OA. Other studies have shown they may improve symptoms as well as corticosteroid injections do. If you're considering hyaluronic acid injections, keep these in mind: