Baker cyst (popliteal cyst)

A Baker cyst, also called a popliteal cyst, is swelling caused by knee joint fluid protruding to the back of the knee (popliteal area of the knee).

A Baker's cyst is usually the result of a problem with your knee joint, such as arthritis or a cartilage tear. Both conditions can cause your knee to produce too much fluid, which can lead to a Baker's cyst. Treating the larger problem usually relieves the swelling and discomfort of a Baker's cyst.

Symptoms and signs

These cysts occur most often in adults between 55 and 70, and in children between 4 and 7 years old.

It may be asymptomatic however, usually there is:

  • Swelling behind the knee
  • Pain and tightness


A noninvasive imaging scan, such as an ultrasound or a magnetic resonance imaging (MRI) scan, can help distinguish between a simple cyst and a tumor.


It is important to treat the cause of the cyst besides the cyst itself. By removing the cyst without the removal of the initiating cause there will remain a chance that the cyst may recur.

  • Fluid drainage is associated with a high recurrence rate.
  • Injection of corticosteroids in the cyst usually decreases the amount of fluid in the cyst and may decrease the pain but doesn't prevent recurrences.

Surgical excision (removal) of the cyst if it is large enough to cause distress or removal of the torn ligament if that has been determined to be the cause of the cyst.

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