A Baker’s cyst is a fluid-filled swelling that develops at the back of the knee. It may be a feature of disorders such as osteoarthritis and rheumatoid arthritis and it may also be caused by a knee injury. Most cysts are painless. Occasionally a cyst may rupture, causing pain in the calf.
In many cases, the cyst disappears by itself.
A large or painful cyst may be treated with pain relievers and corticosteroids to reduce inflammation. Rarely, a cyst may need to be drained or surgically removed