If you have osteoarthritis of the knee or another knee condition that causes pain and stiffness, an injection of hyaluronic acid is a treatment option that may provide relief. This type of injection helps lubricate the joint so that it works more smoothly.

How do hyaluronic acid joint injections for knee pain work?

In a normal, healthy joint, a fluid called hyaluronan provides lubrication. However, if you have osteoarthritis, there is less supply of this fluid. Hyaluronic acid joint injections supplement the joint’s hyaluronan with hyaluronic acid.

It’s a simple procedure that is performed in the office, in which your doctor injects hyaluronic acid directly into the area around the joint. How often you’ll need injections will depend on the specific type of hyaluronan preparation used, but most people have one injection per week for three to five weeks.

If the treatment is effective, you may see results within days—although it may take more than one injection to make the pain go away—and the relief often lasts for several months. In some cases, your doctor may recommend repeat courses. At present, this treatment is only FDA-approved for people with osteoarthritis of the knee, though some patients opt to try the treatment on other joints.

Are there any precautions for HA injections?

There are few side effects to hyaluronic acid joint injections, although some people do have a mild reaction that causes temporary pain and swelling in the joint. It is, however, important to not strain the affected joint after receiving the injections. You should avoid any strenuous activities—such as jogging, tennis, heavy lifting or even being on your feet for long periods—for two days after the treatment.