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Popliteal Cyst / Baker's Cyst

What is a 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 of the knee. Popliteal cysts are usually caused by osteoarthritis or other internal damage inside the knee joint. The cyst occurs as fluid is produced in the knee due to inflammation or irritation and then pressure causes the out-pouching.

What are the symptoms of a popliteal cyst?

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 caused by something else and not the popliteal cyst.

How is a popliteal cyst diagnosed?

A popliteal cyst is diagnosed through a 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, treatment will be individualized to the patient, but it is usually targeted towards treating a different knee problem other than the cyst. 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.

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