A Baker’s cyst, also called a popliteal cyst, is a fluid-filled swelling that develops at the back of the knee. It is caused by a problem with the knee joint or the tissue behind it.
The swelling may cause:
- pain in the knee and calf
- a build-up of fluid around the knee
- occasionally locking or clicking in the knee joint
However, it may cause no symptoms at all.
Causes of a Baker's cyst include:
You can reduce the swelling and relieve any pain using ice, over-the-counter painkillers and bandages. The cyst may go away when the condition causing it has been treated. Find out more about treating a Baker's cyst.
A Baker's cyst is more common in women than men, probably because women are more likely to develop osteoarthritis and rheumatoid arthritis. It usually develops in people aged over 40, although it can affect people of any age, including children.
When to see your GP
See your GP if your cyst causes you problems and does not go away. It's important that any condition that causes it, such as arthritis, is properly managed.
In some cases, particularly if it's caused by osteoarthritis, the cyst may not go away and surgery may be needed to drain or remove it.
