A Baker's cyst is an abnormal swelling of a bursa (a fluid-filled sac) behind the knee.
No one really knows what causes a Baker's cyst. However, a cyst can occur when the lining of the knee joint produces too much fluid after an injury or in certain kinds of arthritis.
You may have pain, swelling, or a feeling of fullness in the area behind the knee.
Your health care provider will examine your knee and find a bulge in the back of your knee. You may need to have a magnetic resonance image (MRI) or an arthrogram to help the health care provider determine if you have a Baker's cyst. For an arthrogram, dye is injected into your knee and then an x-ray is taken to look at the joint.
The initial discomfort of a Baker's cyst may be treated by wearing an elastic bandage. Your provider may prescribe anti-inflammatory medicine, the cyst may be drained, or an operation may be performed to remove the cyst. Sometimes the cyst goes away on its own. If the cyst does not cause bothersome symptoms, it may not be treated.
There is really no way to prevent a Baker's cyst from forming.
Disclaimer: This content is reviewed periodically and is subject to change as new health information becomes available. The information provided is intended to be informative and educational and is not a replacement for professional medical evaluation, advice, diagnosis or treatment by a healthcare professional.
HIA File BJM3269F.HTM Release 9.0/2006
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