Popliteal Cyst / Baker's Cyst

What is popliteal cyst?

A popliteal or Baker’s cyst refers to a benign cyst that develops in the back of the knee. It is an out-pocketing of joint fluid that originates from inside the knee joint and extrudes into the back area of the knee. Popliteal cysts are usually caused by osteoarthritis or other internal derangement inside the knee joint. The cyst occurs as fluid is produced in the knee related to inflammation or irritation and then pressure causes the out-pouching.

What symptoms does a popliteal cyst cause?

Usually there is no pain or discomfort associated with a popliteal cyst. Sometimes there may be a sense of pressure behind the knee. Rarely the cyst can rupture, causing pain and swelling behind the knee and along the leg. It is important to understand that most of the time when someone has knee pain and a popliteal cyst, the knee pain is usually from another cause and the popliteal cyst is not the main problem.

How is a popliteal cyst diagnosed?

A popliteal cyst is diagnosed via physical examination by your doctor. It can also be seen on ultrasound, MRI, and X-rays, though these studies are not always needed to make the diagnosis.

How is a popliteal cyst treated?

A popliteal cyst usually doesn’t need treatment. If there is pain involved then treatment will be individualized to the patient, but it is usually directed to the inciting knee problem more than the cyst itself. It is important that a physician has evaluated the knee and confirmed that the diagnosis is a popliteal cyst, since there are a variety of other less common things that can cause swelling and pain in the back of the knee.