Baker'S Cyst

1 What is Baker's Cyst?

A Baker's cyst, also known as a popliteal cyst is a swelling that usually occurs behind the knee.

The cyst is filled with joint fluid or synovial fluid, and is commonly a result of a knee joint problem such as arthritis or a cartilage tear.

Both of these conditions cause the knee joint to produce excessive amounts of fluid, which leads to the formation of a Baker's cyst.

The pain becomes worse when you flex or extend your knee during activity.

Treatment of the underlying cause may provide some relief.

2 Symptoms

Baker's cyst, sometimes, may not cause any symptoms or pain.

The signs and symptoms, when present include the following:

  • Swelling at the back of your knee, and sometimes in the leg or calf area
  • Knee pain
  • Stiffness and inability to fully bend the knee
  • If the cyst ruptures, bruising may occur on the back of the knee and calf area
  • Your symptoms can worsen after physical activity or if you remain in the standing position for long periods of time

If you have painful swelling behind the knee, consult your doctor.

Sometimes, similar symptoms occur if there is a blood clot or deep venous thrombosis, which are serious conditions that require immediate medical treatment.

3 Causes

The main cause of Baker's cyst is knee swelling.

Knee swelling is a result of the increased production of synovial fluid that lubricates the knee joint.

The accumulation of synovial fluid within the popliteal bursa (area on the back of your knee) causes pressure to build up, resulting in the bulged area called Baker's cyst.

This usually occurs because of inflammation in the knee joint that comes with the following conditions:

4 Making a Diagnosis

A Baker's cyst can be diagnosed upon physical examination alone.

However, as few signs and symptoms of a Baker's cyst appear similar to those of more severe conditions such as a blood clot, aneurysm or tumor, your doctor may advise the following noninvasive imaging studies:

Make a list of your symptoms, including the ones that seem unrelated to your immediate problem.

Some basic questions you can ask your doctor include:

  • What is the reason for this cyst developing?
  • What tests should be done?
  • Do these tests need special preparation?
  • Is Baker's cyst a temporary or chronic problem?
  • What are the types of treatment available, and which one do you recommend?
  • Are there any side effects expected from treatment?
  • What self-care steps can I take?
  • Do I need to restrict any activity? If so, to what extent and for how long?
  • How can I manage other medical conditions which I am suffering from?

Your doctor may also ask you a number of questions, such as:

  • When did your symptoms start?
  • Do you feel the pain or stiffness all the time, or is the pain intermittent and worsens with activity?
  • Do you feel as if your knee is unstable?
  • What is the severity of your symptoms? Is there anything that improves your symptoms?

5 Treatment

In most cases, no treatment is required as a Baker's cyst resolves on its own.

For conditions where the cyst is painful and large enough, your doctor may advise the following treatments:

  • Medication: Your doctor can directly inject a steroid medication such as cortisone, into your knee to reducethe joint inflammation. This relieves pain, but may not prevent the recurrence of the cyst.
  • Fluid drainage: Your doctor may drain out the fluid collected in the knee joint with the help of a needle. This technique is called needle aspiration, and is often undertaken with ultrasound guidance.
  • Physical therapy: Application of ice, a compression wrap, and use of crutches may help decrease the pain as well as swelling. Your physical therapist will teach some gentle range-of-motion and knee muscle strengthening exercises that help relieve your symptoms and preserve the functions of your knee.

Most often, doctors recommend treatment for the underlying cause of the cyst.

If your doctor has found out that a cartilage tear is the cause for the overproduction of synovial fluid, surgical removal or repair of the torn cartilage is recommended.

Surgical treatment is rarely needed for Baker's cysts associated with osteoarthritis, as it usually improves with conservative treatment methods.

6 Lifestyle and Coping

There are different ways to adapt your lifestyle in coping with Baker's cyst.

If arthritis has been causing the Baker's cyst, your doctor will advice you to follow certain measures such as:

Following the R.I.C.E. principles. The acronym ""RICE"" stands for rest, ice, compression and elevation.

  • Rest your leg: Restrict certain activities that may stress your knee.
  • Ice your knee: The application of ice over the affected area reduces pain and swelling
  • Compress your knee with the application of a wrap, sleeve or brace
  • Elevate your leg whenever possible, particularly while sleeping during the night.


Medications such as ibuprofen (Advil, Motrin IB), naproxen sodium (Aleve, others), acetaminophen (Tylenol, others), and aspirin may reduce pain.

Follow the dosage instructions printed on the package. Taking more than the recommend dosage may be harmful.

Physical activity

Doing so will decrease the irritation in your knee joint.

Your doctor will advise on the time period for which you need to limit your physical activity, and alternative forms of exercises will be suggested in the meantime.

7 Risks and Complications

A rare complication of Baker's cyst is rupturing, causing leakage of synovial fluid into the calf region.

This results in:

  • Sharp knee pain
  • Redness and swelling in the calf or a feeling as if water is flowing down your calf region

These signs and symptoms resemble those of a venous blood clot that occurs in the leg.

If you develop any swelling or redness in your calf region, seek prompt medical attention so that a more serious cause of your symptoms can be ruled out.

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