The knee consists of a fluid called synovial fluid, which reduces friction between the bones of the knee joint while you move your leg. Sometimes this fluid is produced in excess, resulting in its accumulation in the back of your knee. A Baker's cyst or popliteal cyst is a fluid-filled swelling that develops into a lump behind the knee. This causes stiffness, tightness and pain behind your knee. It is commonly seen in women and people aged over 40 (although it can develop at any age).
What are symptoms of a Bakers cyst?
A Baker's cyst, in some cases, does not cause any pain and may go unnoticed. However, you may experience symptoms such as swelling behind your knee and legs, stiffness behind the knees, slight pain in the knee towards the upper calf (especially when you bend your knee or straighten it completely). Pain can become severe when you flex your knee and when you are active. Sometimes the cyst can leak and the fluid can drain into the tissues of the lower leg, causing swelling and redness.
What causes a Bakers cyst?
A Baker's cyst is caused by any underlying condition that causes an excess accumulation of joint fluid such as rheumatoid arthritis, osteoarthritis and gout, an injury to the knee, or inflammation of the knee joint.
How can it be diagnosed?
When you present with the above symptoms, your doctor will review your medical history and perform a thorough physical examination of your knee. Further tests such as ultrasound scan and MRI may be recommended in order confirm the diagnosis of Baker's cyst.
How do you treat it?
Most often, a Baker's cyst does not require treatment and may disappear on its own. However, if the cyst is large and causes a lot of pain, the following treatments may be performed:
- Medications: Your doctor may recommend an injection of corticosteroid into your knee to reduce pain. However, this doesn't always prevent the recurrence of the cyst.
- Fluid drainage: Fluid from your knee or the cyst is drained using a needle that is guided by ultrasound. Steroid Corticosteroid injections sometimes follow fluid drainage to help reduce inflammation and pain.
- Physical therapy: Your doctor may suggest the application of ice and a compression wrap or crutches to help reduce the pain and swelling. He/she may also include strengthening and range-of-motion exercises for the muscles around the knee.
- Surgery: Your doctor may treat the underlying cause of the accumulating joint fluid rather than the Baker's cyst itself. For example if a meniscal tear is causing the over production of synovial fluid, arthroscopic surgery may be recommended to manage the meniscal tear.
Depending on your condition, your doctor will determine the best treatment that will help alleviate your symptoms of Baker's cyst.