Baker's Cyst

Baker's Cyst:

A Baker's cyst is a pocket of fluid that forms a lump behind the knee. It is also called a popliteal cyst.

A Baker's cyst is caused when excess joint fluid is pushed into one of the small sacs of tissue behind the knee. When this sac fills with fluid and bulges out, it is called a cyst. The excess fluid is usually caused by conditions such as rheumatoid arthritis or osteoarthritis that irritate the knee. It may also be caused by an injury.

Often a Baker's cyst causes no pain. When symptoms occur, they may include:
Tightness or stiffness behind the knee.
Swelling behind the knee that may get worse when you stand.
Slight pain behind the knee and into the upper calf. You are most likely to feel this when you bend your knee or straighten it all the way.

Sometimes the pocket of fluid behind the knee can tear open and drain into the tissues of the lower leg. This can cause swelling and redness in that part of the leg.

Your doctor will examine your knee and ask you questions about your past health and when the pain and swelling started.
Your doctor may order tests, such as anMRI, to see a picture of the inside of your knee.