Baker's cyst, also known as a cyst in the popliteal fossa, is a lump that appears on the back of the knee due to the accumulation of fluid in the joint, causing pain and stiffness in the area that worsen with the knee extension movement and during physical activity.
Generally, a Baker's cyst is the result of other knee problems, such as arthritis, meniscus damage or cartilage wear and, therefore, does not need treatment, disappearing when the disease that causes it is controlled. The most common is that it is located between the medial gastrocnemius and the semimembranous tendon.
However, although rare, a Baker's cyst can rupture causing severe pain in the knee or calf, and it may be necessary to treat it in the hospital with surgery.
Baker's cyst symptoms
Usually, a baker's cyst has no obvious symptoms, being discovered in an examination performed for any other reason, or during the evaluation of the knee, by the orthopedist or physiotherapist.
Some signs and symptoms that may indicate that there may be a baker cyst in the knee are:
- Swelling behind the knee, as if it were a ping pong ball; Knee pain; Stiffness when moving the knee.
When symptoms of knee problems arise, it is recommended to consult an orthopedist for exams, such as ultrasound of the knee or MRI, and diagnose the problem, initiating the appropriate treatment. The X-ray will not show the cyst but it can be useful to assess osteoarthritis, for example.
Generally, the cyst can be palpated when the person is lying on his stomach with the leg straight and when the leg is bent at 90º. It is good to check that the cyst has well-defined edges and moves up and down whenever the person raises or lowers the leg.
When a Baker's cyst ruptures, the person feels a sharp and sudden pain in the back of the knee, which can radiate to the 'potato of the leg', sometimes being like a deep vein thrombosis.
Treatment for Baker's Cyst
Treatment for Baker's cyst in the knee is usually not necessary, however, if the patient has a lot of pain, the doctor may recommend physical therapy treatment that should include at least 10 consultations to relieve symptoms. The use of the ultrasound device can be useful for reabsorption of the cyst liquid content.
In addition, cold compresses or injections of corticosteroids into the knee can also be used to reduce joint inflammation and relieve pain. Aspiration of the liquid can also be a good solution to remove the baker's cyst, but it is only recommended when there is severe pain, as a way of relieving the symptoms because the possibility of the cyst reappearing is great.
When a Baker's cyst ruptures, it may be necessary to have surgery to aspirate the excess fluid from the knee, through an arthroscopy.
Learn more about How to Treat Baker's Cyst.
