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 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.
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:
* Swelling behind your knee, and sometimes in your leg
* Knee pain
* Texture similar to a balloon filled with water
When to see a doctor
If you're experiencing pain and swelling behind your knee, see your
doctor to determine the cause. Though unlikely, a bulge behind your knee
may be a sign of a more serious condition, such as a tumor or a
popliteal artery aneurysm, rather than a fluid-filled cyst.
The cartilage and tendons in your knee rely on a lubricating fluid
called synovial (si-NO-vee-ul) fluid. This fluid helps your leg swing
smoothly and reduces friction between the moving parts of your knee.
Synovial fluid circulates throughout your knee and passes in and out of
various tissue pouches (bursae) throughout your knee. A valve-like
system exists between your knee joint and the bursa on the back of your
knee (popliteal bursa). This regulates the amount of synovial fluid
going in and out of the bursa.
But sometimes the knee produces too much synovial fluid, resulting in
buildup of fluid in the bursa and what is called a Baker's cyst. This
can be caused by:
* Inflammation of the knee joint, such as occurs with various types of arthritis
* Knee injury, such as a cartilage tear
Rarely, a Baker's cyst bursts and synovial fluid leaks into the calf region causing:
* Sharp pain in your knee
* Sometimes, redness of your calf or a feeling of water running down your calf
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.
Preparing for your appointment
You're likely to first see your family doctor or a general practitioner.
However, you may then be referred to a doctor who specializes in
disorders affecting the bones, joints and muscles (an orthopedist or
orthopedic surgeon, rheumatologist, or physical medicine and
Because 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, and what to expect from
What you can do
* Write down any symptoms you're experiencing, including any that
may seem unrelated to the reason for which you scheduled the
* Write down key personal information, including recent life changes.
* Make a list of all medications, vitamins and supplements that you're taking.
* Write down questions to ask your doctor.
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:
* What caused this cyst to develop?
* What kinds of tests do I need? Do these tests require any special preparation?
* Is a Baker's cyst temporary or long lasting?
* What treatments are available, and which do you recommend?
* What types of side effects can I expect from treatment?
* What steps can I take on my own that might help?
* Do I need to limit my activity? If so, how much? And, for how long?
* I have another health condition. How can I best manage these conditions together?
In addition to the questions that you've prepared to ask your doctor,
don't hesitate to ask questions during your appointment anytime you
don't understand something.
What to expect from your doctor
Your doctor is likely to ask you a number of questions, such as:
* When did you first begin experiencing symptoms?
* Do you feel pain or stiffness all the time, or does the pain come and go with activity?
* Does your knee swell, feel unstable or lock?
* How severe are your symptoms?
* Does anything seem to improve your symptoms?
* What, if anything, appears to worsen your symptoms?
What you can do in the meantime
If the cyst isn't causing you pain, you may not need to do anything
prior to seeing your doctor. However, if the cyst is causing symptoms,
such as pain and stiffness, taking the following steps may help:
* Use a cold pack or ice wrapped in a protective covering to ice the affected area when it's bothering you.
* Rest your affected knee and keep the leg elevated whenever possible.
* Take an over-the-counter pain-relieving medication to ease your
symptoms. Nonsteroidal anti-inflammatory medications (NSAIDs) — such as
aspirin, ibuprofen (Advil, Motrin, others) and naproxen (Aleve, others) —
can reduce pain and inflammation, while acetaminophen (Tylenol, others)
can ease pain.
* Use a knee sleeve or brace for compression.
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 or tumor, your doctor may
order noninvasive imagine tests, including:
* Magnetic resonance imaging (MRI)
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:
* Physical therapy. Icing, a compression wrap and crutches may help
reduce pain and swelling. Gentle range-of-motion and strengthening
exercises for the muscles around your knee also may help to reduce your
symptoms and preserve knee function.
* Fluid drainage. Your doctor may drain the fluid from the knee
joint using a needle. This is called needle aspiration and is often
performed under ultrasound guidance.
* Medication. Your doctor may inject a corticosteroid medication,
such as cortisone, into your knee to reduce inflammation. This may
relieve pain, but it doesn't always prevent recurrence of the cyst.
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.
In some instances, particularly if you have osteoarthritis, the cyst may
not go away even after your doctor treats the underlying cause. If the
cyst doesn't get better, causes pain and interferes with your ability to
bend your knee, or if — in spite of aspirations — fluid in the cyst
recurs and hinders knee function, you may need to be evaluated for
surgery to remove the cyst.
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 to reduce the
inflammation and lessen the production of synovial fluid:
* Follow the P.R.I.C.E. principles. These letters stand for
protection, rest, ice, compression and elevation. Protect your leg by
using crutches to take the weight off the knee joint and to allow
pain-free walking. Rest your leg. Ice the inflamed area. Compress your
knee with a wrap, sleeve or brace. And elevate your leg when possible,
especially at night.
* Try nonsteroidal anti-inflammatory drugs (NSAIDs) or
acetaminophen. NSAIDs, such as aspirin, ibuprofen (Advil, Motrin,
others), naproxen (Aleve, others) and similar drugs, can help relieve
pain, as can acetaminophen (Tylenol, others). Prescription NSAIDs can
provide higher doses and greater potency than over-the-counter NSAIDs.
* Scale back your physical activity. Doing so will reduce irritation
of your knee joint. Your doctor can offer you guidance on how long you
need to reduce your activity levels, and may be able to suggest
alternative forms of exercise you can do in the meantime.