A Baker's cyst is a fluid-filled cyst that causes a bulge and a feeling of tightness behind your knee. The pain can get worse when you fully flex or extend your knee or when you're active.
A Baker's cyst, also called a popliteal (pop-LIT-e-ul) 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.
Although a Baker's cyst may cause swelling and make you uncomfortable, treating the probable underlying problem usually provides relief.
Swelling on the back of one knee may be a Baker's cyst. A Baker's cyst can form when joint-lubricating fluid overfills a cushioning pouch (bursa) at the back of your knee. ...
In some cases, a Baker's cyst causes no pain, and you may not even notice it. If you do experience signs and symptoms, you may notice:
Your symptoms may be worse after you've been active, or even if you've just been standing for a long time.
When to see a doctor
A lubricating fluid called synovial (sih-NO-vee-ul) fluid helps your leg swing smoothly and reduces friction between the moving parts of your knee.
But, sometimes the knee produces too much synovial fluid, resulting in buildup of fluid in an area on the back of your knee (popliteal bursa), causing a Baker's cyst. This can happen because of:
Rarely, a Baker's cyst bursts and synovial fluid leaks into the calf region, causing:
These signs and symptoms closely resemble those of a blood clot in a vein in your leg. If you have swelling and redness of your calf, you'll need prompt medical evaluation to rule out a more serious cause of your symptoms.
Preparing for your appointment
Because doctor's appointments can be brief, and there's often a lot of ground to cover, it's a good idea to arrive well prepared. Here's some information to help you get ready for your appointment, as well as what to expect from your doctor.
What you can do
Your time with your doctor may be limited, so preparing a list of questions can help you make the most of your time together. List your questions from most important to least important in case time runs out. For a Baker's cyst, some basic questions to ask your doctor include:
In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask additional questions during your appointment.
What to expect from your doctor
What you can do in the meantime
Tests and diagnosis
A Baker's cyst can often be diagnosed with a physical exam. However, because some of the signs and symptoms of a Baker's cyst mimic those of more-serious conditions, such as a blood clot, aneurysm or tumor, your doctor may order noninvasive imaging tests, including:
Treatments and drugs
Many times, no treatment is required and a Baker's cyst will disappear on its own.
If the cyst is very large and causes a lot of pain, your doctor may use the following treatments:
Typically though, doctors treat the underlying cause rather than the Baker's cyst itself.
If your doctor determines that a cartilage tear is causing the overproduction of synovial fluid, he or she may recommend surgery to remove or repair the torn cartilage.
Baker's cysts associated with osteoarthritis may stay swollen even if you're receiving arthritis treatment. You and your doctor may discuss surgery to remove the cyst if it doesn't resolve and it affects your joint movement. Baker's cyst removal may be an option for a cyst that repeatedly refills after you have it drained with a needle.
Lifestyle and home remedies
If your doctor determines that arthritis is causing the cyst, he or she may advise you to take some or all of the following steps:
Last Updated: 2012-08-01
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