Osteoarthritis of the Knee

What is osteoarthritis?

Osteoarthritis 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). Osteoarthritis in the knee can be a painful problem.

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 and examining your knee. Your doctor may want to take x-rays of your knee or test your blood. X-rays can help your doctor see how serious the problem is. Blood tests can rule out other forms of arthritis.

How will my doctor treat my osteoarthritis?

Medicines and physical therapy can help manage the pain caused by osteoarthritis. Your doctor may tell you to use pain-relieving creams or sprays that you apply to your skin around your knee. Your doctor may also tell you to take oral medications such as acetaminophen (brand name: Tylenol) to relieve pain or anti-inflammatory medicines that range from over-the-counter medicines such as aspirin and ibuprofen (one brand name: Advil) to prescription-only drugs.

Physical therapy is a special exercise program with a trained therapist who helps you regain movement and flexibility of your knee while also trying to relieve pain. These exercises may also strengthen your muscles around your knee for more stability and balance. You will almost certainly need physical therapy if you choose to have knee surgery.

Are there other options?

Yes. If oral medicine and physical therapy don't help your knee enough, your doctor may consider giving you an injection ("shot") with pain medicine (called anesthetic). It can stop the pain for days to weeks. Adding another medicine (called a corticosteriod) to the anesthetic may keep the pain away longer. If this doesn't help enough, your doctor may talk to you about surgery or hyaluronic acid injections.

What are hyaluronic acid 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. Injections can put more hyaluronic acid into your knee joint to help protect it.

Hyaluronic acid injections may give you more pain relief than oral medicines. These injections can help the pain stay away for 6 months to a year, sometimes longer. Unfortunately, these injections don't help everyone.

Hyaluronic acid injections are also expensive but many health insurance programs cover them. Hyaluronic acid injections may be an option for you. Your doctor will talk with you about the pros and cons of hyaluronic acid injections and whether they are right for you.

What about surgery?

According to the American Academy of Orthopaedic Surgeons, about 1 in 4 people with osteoarthritis of the knee will eventually need surgery. Surgical options include:
  • Arthroscopy is done with a small scope (or camera) inserted through tiny cuts a surgeon makes in your knee. With the scope, the surgeon can see how badly your knee has been damaged by osteoarthritis. With other small instruments, the surgeon can remove damaged parts of the knee joint (this is called debridement) and clean or flush the joint to remove any loose parts (called lavage or irrigation) that may be causing your pain. Arthroscopy is not for everyone and may only provide temporary relief from pain or delay the need for other surgeries.
  • Osteotomy is a surgery that repositions or reshapes the bones in your knee where osteoarthritis has caused damage. This procedure can only be done when only one area or side of your knee is damaged. The procedure changes the position or alignment of the knee so your weight shifts away from the damaged area. This procedure restores movement in your knee and relieves the pain. However, people who have an osteotomy may need knee replacement surgery in the future.
  • Arthroplasty is also called joint or knee replacement therapy. A surgeon removes the part of the knee damanged by osteoarthritis and replaces it with an artificial joint made from metals and plastic. All or part of the knee joint may be replaced in this procedure. Although recovery may take a long time depending on the extent of your surgery, the results of arthroplasty are often successful. Knee replacement therapy can help put an end to your pain and improve or restore movement of your knee.

More Information

For more information talk to your doctor.

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Written by familydoctor.org editorial staff.

Intra-articular Hyaluronic Acid Injections for Knee Osteoarthritis by DY Wen, M.D. (American Family Physician August 1, 2000, http://www.aafp.org/afp/20000801/565.html)

Reviewed/Updated: 11/06
Created: 09/00