William Morrant Baker was a 19th century surgeon who first described the condition termed “Baker’s Cyst.” It is also called a popliteal cyst. It forms when excess synovial fluid accumulates in the hollow at the back of the knee joint and forms a bulge. It does not necessarily develop with symptoms other than the protrusion; however, it can present with swelling, stiffness in the joint and pain. Large cysts can also inhibit range of motion in the knee joint.
The Baker’s cyst usually occurs when there is a problem with the knee joint. Arthritis and cartilage tears are often the source of this condition. They can cause the production of excess synovial fluid and this can lead to the development of a cyst in the back of the knee.
The synovial fluid lubricates joints in the body. In your leg, it helps you move the leg freely and reduces the friction in the moving parts of your knee. An injury to the knee, or inflammation such as that which occurs with arthritis, increases the production of the fluid.
Diagnosis of Baker’s Cyst
A lump at the back of the knee is a good indication that you may have a Baker’s Cyst. A physical examination will help confirm it. Other problems such as a blood clot, aneurysm or tumor need to be ruled out, which makes it important for you to seek medical attention if you notice a protrusion in the hollow of your knee.
Non-invasive imaging tests may be used to rule out these other possibilities. Ultrasound scans, also called sonograms, use high-frequency sound waves to generate an image of what is going on inside the body. X-rays may also be used in the diagnosis. These produce pictures of the bones and other structures in the knee. Magnetic resonance imaging, or MRI, is also used to see the structures of the knee joint. This procedure uses radio waves in conjunction with a large magnet to produce the images.
After ruling out other conditions and confirming the presence of Baker’s cyst, you doctor will create a treatment plan. Treatment will be determined by the size of the cyst and whether or not it is causing problems or discomfort.
In some instances a Baker’s cyst will resolve on its own without any intervention. When it is caused by arthritis or some other problem, treatment of that condition may also result in the cyst going away on its own. If treatment for the condition does not make it disappear, your doctor may aspirate the fluid with a needle.
Large cysts may need additional treatment. Sometimes medication is required. A corticosteroid injection is used to reduce inflammation in the knee. This often reduces pain; however, the downside is that it does not necessarily prevent the cyst from appearing again.
Physical therapy is also used to help relieve the symptoms of a Baker’s cyst. Pain and swelling may be reduced with icing the cyst and using a compression wrap. You may be advised to use crutches to help alleviate pain and swelling, too. Exercises for strengthening and gentle range-of motion movements may also be recommended to aid in the reduction of symptoms. These exercises help preserve the function of your knee by working the muscles around it.
When a Baker’s cyst is caused by an injury such as a tear in the cartilage, treating the cause should relieve the symptoms. For example, surgery to repair a cartilage tear should stop the over production of synovial fluid and the cyst should go away.
Treatment for osteoarthritis, if that is determined to be the cause, often resolves the condition. Surgery is not usually required for cysts related to arthritis. Rest, icing the knee, using compression with a wrap, sleeve or brace and elevating the leg are often enough. Over-the-counter pain relievers will help with pain and reducing your physical activity will help alleviate irritation of the joint.
While a Baker’s cyst is not necessarily a major problem, it can compromise your activity. If you find this is the case, contact Silicon Valley Orthopaedics. Dr. Nic Gay or Dr. Masi Reynolds will provide you with a comprehensive examination, make a diagnosis and suggest a treatment plan. Call today to schedule your consultation.