Draining cyst may not eliminate problem

August 20, 2008|Medical Edge Mayo Clinic

I am a 59-year-old man who had a Baker's cyst 20 years ago. It returned three years ago. I had surgery, which was supposed to take care of things. I have had it drained twice, only to have it return in two days. My leg is getting worse, and I'm limping. Is knee replacement the only solution?

A Baker's cyst can cause swelling behind the knee and pain and stiffness in the joint, but it is usually not a stand-alone medical condition. Rather, a Baker's cyst typically results from an underlying problem in the knee joint, for example, a form of arthritis or a knee injury. In many cases, when the underlying condition is treated, the cyst often goes away.

Circulating through the knee is a lubricating (synovial) fluid that reduces friction between the moving parts of the joint. As it flows throughout the knee, this fluid passes in and out of small tissue pouches (bursa). Between the knee joint and the bursa at the back of the knee (popliteal bursa), a valve-like system regulates the amount of fluid within the knee.

A knee joint affected by arthritis, cartilage (meniscus) tears, or other disorders, may produce too much synovial fluid - sometimes called "water on the knee." The excess fluid is pushed out of the joint into the popliteal bursa, causing it to enlarge. The result is a Baker's, or popliteal, cyst.

The challenge is to determine if the cyst is the problem, or if the cyst stems from another disorder. A large Baker's cyst that causes discomfort and affects movement can be drained. But if an underlying knee problem goes untreated, draining fluid from the cyst is not a long-term solution. Most cysts will return, unless any underlying problem is resolved. You should work with your doctor to determine what's wrong with your knee.

Generally, Baker's cysts don't cause limping, which suggests that your pain may be due to arthritis - a condition that develops when the cartilage in your knee wears down over time. If you have arthritis, knee replacement is not the only option. Depending on the severity of your condition and any prior treatment you've had, medications, physical therapy, bracing, injections and other techniques may significantly reduce your symptoms, perhaps allowing you to avoid or delay surgery.

In rare cases, a Baker's cyst may not go away despite treatment of an underlying medical condition in the knee joint. Surgery to remove the cyst may be an option.

In some cases, a Baker's cyst can rupture, resulting in sudden calf pain and swelling. A ruptured Baker's cyst is often mistaken for a blood clot in the leg (deep vein thrombosis), a serious condition that requires immediate treatment. Because the two conditions can look alike, if you have swelling and redness of your calf, seek prompt medical attention.


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