BAKER’S CYST
A baker’s cyst is a type of fluid-filled swelling at the back of the knee.
- The back of the knee is also referred to as the popliteal area of the knee
- Also known as a popliteal cyst, baker’s cyst causes a bulge at the back of the knee, leading to tightness and restriction of movement.
- The pain can get worse especially when the knee is extended or fully flexed.
- Rarely, a baker’s cyst can burst and become complicated by spread of fluid down the leg between the muscles of the calf. A ruptured baker’s cyst can produce acute pain behind the knee and in the calf as well as swelling of the calf muscles.
- Around 20% of people have baker’s cyst and they occur commonly in people between 35 to 70 years of age.
- The condition is named after DR. William Morrant Baker, the first physician who described it
CAUSES
The knee comprises of bone, tendons, and cartilage. The synovial fluid lubricates the cartilage and tendon, and this helps the leg move smoothly and reduces friction between the moving parts of the knee
The synovial fluid circulates through the bursae located in each knee. A valve-like system regulates the flow of the synovial fluid between the popliteal bursa (an area on the back of the knee) and the knee joint.
An overproduction of the synovial fluid in the knee can accumulate in the popliteal bursa, causing Baker’s cyst. This can happen because of:
- An inflammation of the knee joint, such as occurs in almost any form of arthritis
- Injury or trauma to the knee, such as cartilage tear. They are common among athletes.
SYMPTOMS
Some patients may experience no pain and may not notice the cyst. However, if symptoms occur, they may include.
- Knee pain
- Swelling behind the knee, and sometimes in the leg
- Stiffness and inability to extend or fully flex the knees
DIAGNOSIS AND TREATMENT
A Baker’s cyst can be diagnosed with a physical exam where the doctor will assess your knee and feel the swelling.
The doctor may recommend a non-invasive imaging test including Ultrasound, X-ray, or MRI to rule out other similar conditions such as blood clot, tumor, or aneurysm.
TREATMENT
In some cases, a Baker’s cyst will resolve on its own. However, a large and painful cyst may be treated with the following:
- Corticosteroid injection, a corticosteroid injection such as cortisone may be injected into your knee to reduce inflammation and relieve pain. This treatment doesn’t prevent a reoccurrence
- Needle aspiration, where the doctor drains the excess fluid from the knee joint with a needle under ultrasound guidance.
- Regular, gentle exercises may help strengthen the muscle around the knee and increase the range of motion. Activities that can put more strain on the knee such as squatting, kneeling, heavy lifting, climbing, and even running should be avoided, this can help to prevent pain.
- Ice pack therapy may sometimes be effective in controlling the pain related to Baker’s cyst.
- If the doctor discovers a tear to the cartilage, they may recommend surgery to remove or repair the torn cartilage
- If possible, doctors will treat the underlying cause of the cyst.
- Surgical excision is reserved for cysts that cause extreme pain and limits a patient’s range of motion.