Pain behind the knee and blood clots

by Nathan Wei, MD, FACP, FACR

Nathan Wei is a nationally known board-certified rheumatologist and author of the Second Opinion Arthritis Treatment Kit. It's available exclusively at this website... not available in stores.

Click here: Second Opinion Arthritis Treatment Kit



A door hinge needs oil to swing smoothly, to reduce the friction between its moving parts and to minimize wear and tear.

These cysts occur most often in adults between 55 and 70. As many as one in five people with other knee problems develop a Baker's cyst.

In some cases, a Baker's cyst causes no pain and goes unnoticed. The signs and symptoms that may occur include:

• Swelling behind the knee, and sometimes in the leg or foot
• Knee pain
• Tightness in the back of your knee
• Stiffness


Treating the underlying condition, such as rheumatoid arthritis or a cartilage tear, usually relieves the swelling and discomfort of a Baker's cyst. In rare cases, a bulge behind your knee may be a tumor rather than a fluid-filled cyst.

A noninvasive imaging scan, such as an ultrasound or a magnetic resonance imaging (MRI) scan, can help distinguish between a simple cyst and a tumor, which could be cancerous.

Rarely, a Baker's cyst bursts and synovial fluid leaks into the calf region, causing sharp pain in the knee, swelling and sometimes redness of the calf. These signs and symptoms closely resemble those of a blood clot in the leg. If there is swelling and redness of the calf, a prompt medical evaluation is mandatory because a blood clot may require urgent treatment. If the doctor suspects a blood clot in the leg (deep vein thrombosis), he or she may suggest an ultrasound of the leg or other tests to exclude the possibility of a blood clot.

If the cyst is very large and causes a lot of pain, the physician may use the following treatments:

• Fluid drainage. Your doctor may drain the fluid from the knee joint using a needle. This is called needle aspiration. This should be done using ultrasound guidance. In our clinic, we have had excellent outcomes with this technique.
• Medication. Your doctor may inject a corticosteroid medication, such as cortisone, into the knee to reduce the volume of fluid being produced. This may relieve pain but doesn't always prevent recurrence of the cyst.


If the doctor determines that a cartilage tear is causing the overproduction of synovial fluid, he or she may recommend surgery to remove the torn cartilage. Other helpful hints are:

• Follow the P.R.I.C.E. principles. These letters stand for protection, rest, ice, compression and elevation. Protect the leg by using crutches to take the weight off the knee joint and to allow pain-free walking. Rest the leg. Ice the inflamed area. Compress the knee with a wrap. And elevate the leg, especially at night.
• Try nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen. NSAIDs such as aspirin, ibuprofen (Advil, Motrin, others), naproxen (Naprosyn, Aleve, others) and similar drugs can help relieve pain, as can acetaminophen (Tylenol, others). Prescription NSAIDs can provide higher dosages and greater potency than over-the-counter NSAIDs.
• Scale back physical activity. Doing so will reduce irritation of the knee joint.

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