Baker's cyst

A Baker’s cyst, also known as a popliteal cyst, is a fluid-filled swelling that develops at the back of the knee, causing knee pain and stiffness. The condition is named after a 19th-century doctor and has nothing to do with baking food.

A Baker’s cyst is usually caused by existing problems with the knee joint, such as arthritis.

How common are Baker’s cysts?

A Baker’s cyst can be a very common complication of conditions that can affect the normal working of the knee joint, such as osteoarthritis and rheumatoid arthritis.

Baker’s cysts are more common in women than men. This may be because women are more likely to develop osteoarthritis and rheumatoid arthritis. The condition usually develops in people who are over 40, although it can affect people of any age, including children.

Outlook

In most cases, a Baker's cyst will go when the condition causing it has been treated.

There may be some instances, particularly with osteoarthritis, where the cyst remains. Surgery may be required to drain it.

Glossary

Cyst

A cyst is a fluid-filled sac or cavity in the body.

Joint

Joints are the connection point between two bones that allow movement.

Inflammation

Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.

Pain

Pain is an unpleasant physical or emotional feeling that your body produces as a warning sign that it has been damaged.