Joint fluid helps the knee move smoothly. A Baker cyst develops when there is too much of this fluid. The extra joint fluid is pushed out to the back of the knee. Extra fluid may be caused by:
- Arthritis — osteoarthritis is the most common type associated with Baker cysts
- Cartilage tears, such as a torn meniscus
- Injury or accidents
- Infection in joint
In children, Baker cyst may be related to a problem with the bursa. The bursa is a small fluid filled sac between the bone and soft tissue.
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Your doctor will ask about your symptoms and medical history. A physical exam will be done. The doctor will look for a soft mass in the back of the knee. The range of motion in both knees will be tested and compared. The doctor may also shine a special light through the cyst. This will show that the cyst is filled with fluid and not solid.
Images of the knee occasionally needed to look for the cause and extent of the cyst . Images may be taken with:
- CT scan
- MRI scan
Blood tests may be taken if there may be an infection.
Many Baker cysts resolve on their own without treatment. They usually go away within a 2-year period.
The underlying cause may need treatment. This may include knee repairs or medication to treat medical conditions.
Treatment for the cyst itself may be needed if the cyst is painful or interferes with daily activities. Treatment options include:
- Medications to relieve pain and inflammation such as nonsteroidal anti-inflammatory drugs (NSAIDs)
- Physical therapy to help strengthen muscles around the knee
- Steroid injection
- Draining excess knee fluid
- Surgery—to remove large cysts or repair related knee injuries
This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.
Edits to original content made by Denver Health.
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a (Popliteal Cyst)
Ortho Info— American Academy of Orthopaedic Surgeons http://www.orthoinfo.org
Sports Med—American Orthopaedic Society for Sports Medicine http://www.sportsmed.org
Canadian Orthopaedic Association http://www.coa-aco.org
Canadian Orthopaedic Foundation http://www.canorth.org
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