Baker’s cyst, also known as a popliteal cyst or a synovial cyst, is a fluid-filled lump or growth that develops at the back of the knees.
Baker’s cyst, also known as a popliteal cyst or a synovial cyst, is a fluid-filled lump or growth that develops at the back of the knees. It occurs due to the build-up of synovial fluid in the knee joint thus causing inflammation and swelling of the tissues behind the knee, resulting in pain and stiffness which worsens with activity or when the knee is bent or straightened.
What causes Baker’s cyst?
The knee is made up of multiple components that all work together to enable fluidity and good range of motion. The knee joint contains synovial fluid and fluid-filled sacs known as bursa that provide lubrication and cushioning to reduce friction between our bones.
However, if inflammation or swelling of the knee should occur, the knee responds by producing an excess of synovial fluid, which flows to the popliteal bursa behind the knee, causing it to swell and grow, resulting in a Baker’s cyst.
Inflammation and swelling of the knee can occur due to:
Injury: injuries to the knee such as meniscus injuries, ACL injury/tear, can cause the build-up of synovial fluid in the knee joint, resulting in a Baker’s cyst.
Medical conditions:arthritis such as osteoarthritis and rheumatoid arthritis causes inflammation of joints, thus resulting in a Baker’s cyst. Gout is also a type of arthritis that can eventually result in Baker’s cyst.
What are the symptoms of Baker’s cyst?
In most individuals,they may experience no symptoms other than an obvious lump or growth at the back of their knee.
However, some individuals may experience the following symptoms:
Fluid-filled lump or growth behind the knee
Pain or discomfort
Limited or reduced range of motion
Stiffness in the knee joint
Swelling and inflammation of the knee joint
Reduced ability to bend the affected knee
Inability to fully flex the affected leg
Numbness if the Baker’s cyst has compressed a nerve
If you notice any of the symptoms, make an appointment with an orthopaedic specialist to get an accurate diagnosis and treatment.
Dr Puah KL is our Senior Consultant Orthopaedic Surgeon at Artisan Sports & Orthopaedic Surgery. He used to serve the sports service of Singapore General Hospital - the highest volume trauma centre for orthopaedics in Singapore.
Most individuals with Baker’s cyst do not experience any symptoms other than an obvious growth or lump behind the knee. However, some individuals experience pain and discomfort in relation to the Baker’s cyst.
These individuals may also experience a reduced range of motion and stiffness in the affected knee joint.
Who is at risk of Baker’s cyst?
Baker’s cyst can occur to anyone, however, there are certain factors that increase a person’s risk.
These factors are:
Knee joint injury or conditions: individuals with knee joint injury such as meniscus tears or ACL injuries/tears, or knee conditions such as osteoarthritis or rheumatoid arthritis, are at an increased risk of developing Baker’s cyst.
Age: your risk of developing Baker’s cyst increases with age.
Sports/hobbies: high contact sports or hobbies that put you at a higher risk of knee injuries will by default increase your risk of developing Baker’s cyst.
How is Baker’s cyst diagnosed?
Baker’s cyst is diagnosed in the following ways:
Physical examination and medical history: inform your orthopaedist about any prior knee injury or conditions that may have led to the development of the Baker’s cyst. Physically the area of concern will be examined and several motion tests such as bending and straightening the injured knee will be conducted.
Imaging tests: x-rays will be conducted to identify if arthritis is present, which may identify the cause of your Baker’s cyst. Magnetic resonance imaging (MRI) can also be used to identify other causes of your Baker’s cyst such as ACL tears/injuries and meniscus injuries. Ultrasounds can also be conducted to identify if the lump is fluid-filled.
What are the treatment options for Baker’s cyst in Singapore?
Most of the time, a Baker’s cyst will go away on its own. However, for some individuals, treatment is required to resolve the issue.