A Baker’s cyst is a swelling filled with synovial fluid, which forms behind your knee. Synovial fluid is the lubricating fluid that is usually found inside the knee joint. Baker’s cyst is typically formed by an inter-communication between the posterior joint capsule and the bursa which is lined with synovial cells. Diseases that cause chronic joint effusions such as inflammatory arthritis, crystal deposition diseases, osteoarthritis and internal derangements of the knee are associated with Baker’s cyst. Debris, hemorrhage, loose bodies and synovial proliferation can be present in the cyst. It will often disappear by itself and so you will not need treatment. In some cases a Baker’s cyst causes no pain and so remains unnoticed. The common symptoms of a Baker’s cyst are: swelling behind the knee, pain behind the knee, tightness in the back of the knee, knee stiffness, and difficulty moving the knee joint. There is nothing you can do to make it disappear. If the Baker’s cyst is large and causes a lot of pain, doctors may drain the fluid from the knee joint using a needle. Alternatively, your doctor can also inject a corticosteroid into the knee to reduce the volume of synovial fluid being produced. This will relieve the pain but may not prevent the recurrence of a Baker’s cyst. Rarely, a cyst may burst and leak synovial fluid into the calf region. If this happens there may be a sharp pain at the back of the knee, swelling and sometimes redness of the calf. Advice 1. Cold fomentation with ice pack – wrap ice in a towel and apply for 10-20 minutes – it will reduce swelling and pain 2. Ibuprofen 600 mg after meal if pain occurs. Otherwise avoid it Thanks