A Baker’s cyst is a fluid-filled cyst that creates a bulge and causes tightness behind the knee. A Baker’s cyst, also known as a popliteal cyst, is usually due to a problem with the knee joint, like a tear in the cartilage, or arthritis. Both of which can cause the knee to produce too much fluid, leading to a Baker’s cyst.
A Baker’s cyst can cause no pain in some instances. It may even go unnoticed. If you do have symptoms, they might include the following:
- Swelling and soreness behind your knee
- Knee pain
- Stiffness and inability to fully extend the knee
These symptoms may worsen while active or if you’ve been standing for a long time.
Baker’s Cyst causes
A lubricating fluid called synovial fluid helps your leg swing smoothly, reducing friction in all the moving parts of your knee.
In some cases, the knee produces too much synovial fluid. This can result in buildup of fluid in the back of the knee causing a Baker’s cyst.
In rare cases, the cyst bursts and synovial fluid leaks into the lower leg. This can cause:
- Sharp knee pain
- Calf swelling
- Redness in the calf
- Feeling of water running down your calf
These symptoms are similar to a blood clot in a vein in your leg. If you have swelling and redness of your calf, seek prompt medical attention.
A Baker’s cyst is best diagnosed with a physical exam. However, because some of the signs of a Baker’s cyst mimic those of other, more-serious conditions, like blood clot, aneurysm or tumor, your doctor may require noninvasive imaging tests, including:
- Magnetic resonance imaging (MRI)
Baker’s Cyst treatment
The cyst may drain and disappear on its own. If the cyst causes pain, your doctor may recommend these treatments:
- Medication. Corticosteroid medication injection into the knee to reduce inflammation may relieve pain, but it doesn’t necessarily prevent cyst recurrence.
- Drainage. Your doctor may drain the fluid from the knee joint using needle aspiration completed under ultrasound guidance.
- Physical therapy. Icing, a compression wrap and crutches may help reduce pain and swelling.
Doctors should treat the underlying cause of the cyst. If your doctor determines that a cartilage tear is causing the excess synovial fluid, they may recommend surgery to remove or repair the torn cartilage.
Baker’s cysts linked to osteoarthritis usually improve with arthritis treatment and surgery is rarely needed.
Other treatment options
If your doctor finds that arthritis is the cause they may advise you to do the following:
- Follow RICE principles. These letters stand for rest, ice, compression, and elevation. Rest your leg. Ice your knee. Compress your knee with a wrap, sleeve, or brace. And elevate your leg.
- Take over-the-counter medications. Drugs like ibuprofen (Advil), naproxen sodium (Aleve), acetaminophen (Tylenol), and aspirin can help relieve pain and inflammation.
- Cut your mileage. Your doctor will give guidance on how long you need to reduce your activity.