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Information from Your Family Doctor

Treating Knee Osteoarthritis with Injections


Am Fam Physician. 2000 Aug 1;62(3):572.

  See related article on intra-articular hyaluronic acid injections for knee osteoarthritis.

What is osteoarthritis?

Osteoarthritis is a painful knee problem. It is also called degenerative arthritis or wear-and-tear arthritis. Arthritis is what happens when the tissue that protects the bones wears away. This tissue is called cartilage (say: car-till-edge).

What causes osteoarthritis?

Doctors don't know what causes joint cartilage to wear away. But they do know that osteoarthritis is more common as you get older or if you are very overweight. Sometimes a serious knee injury can bring on arthritis after a few years.

How can my doctor tell if I have osteoarthritis?

Your doctor can find out if you have osteoarthritis by asking you questions about how your knee feels and by giving your knee an exam. Your doctor may want to take x-rays of your knee. These x-rays can help your doctor see how serious the problem is.

How will my doctor treat my osteoarthritis?

First, your doctor will try some medicines to help the pain go away. Next your doctor may want you to have physical therapy. This is a special exercise program with a trained therapist who helps you move your knee in certain ways. If you still have knee pain, your doctor may want to try knee injections.

Your doctor might inject an anesthetic agent. This is a medicine that makes your knee numb. It can stop the pain for a short time—maybe days or a few weeks. Another medicine, called a corticosteroid, can be injected along with the anesthetic. These medicines together might make your pain stay away longer.

In the past few years, a medicine called hyaluronic acid has been used for knee injections. Some hyaluronic acid is already in the fluid in your joints. In people with osteoarthritis, the hyaluronic acid gets thinner. When this happens, there isn't enough hyaluronic acid to protect the joint like it used to. Injections can put more hyaluronic acid into your knee joint to help protect it.

Hyaluronic acid injections can help you in several ways. They may give you more pain relief than oral medicines. If your doctor thinks that you might need surgery on your knee, hyaluronic acid injections can make the pain go away long enough that you might not have to have surgery, or you might be able to wait a while before having surgery. These injections can help the pain stay away for six months to a year, and sometimes longer. Unfortunately, these injections don't help everyone.

Hyaluronic acid injections are expensive. They usually cost more than $600. Many health insurance programs cover these injections.

This handout is provided to you by your family doctor and the American Academy of Family Physicians. Other health-related information is available from the AAFP online at

This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.


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