A Baker’s cyst is a fluid-filled cyst that causes a bulge and a feeling of tightness behind your knee. The pain can get worse when you fully flex or extend your knee or when you’re active.
A Baker’s cyst, also called a popliteal (pop-LIT-e-ul) cyst, is usually the result of a problem with your knee joint, such as arthritis or a cartilage tear. Both conditions can cause your knee to produce too much fluid, which can lead to a Baker’s cyst. Although a Baker’s cyst may cause swelling and make you uncomfortable, treating the probable underlying problem usually provides relief.
There are two ways in which a Baker’s cyst may form: A primary Baker’s cyst A Baker’s cyst may develop just behind an otherwise healthy knee joint. This type of cyst is sometimes referred to as a primary or idiopathic Baker’s cyst. It usually develops in younger people and children. It is thought that in this type of Baker’s cyst there is a connection between the knee joint and the popliteal bursa behind the knee. This means that synovial fluid from inside the joint can pass into the popliteal bursa and a Baker’s cyst can form. A secondary Baker’s cyst Sometimes a Baker’s cyst can develop if there is an underlying problem within the knee, such as arthritis (including osteoarthritis and rheumatoid arthritis), or a tear in the meniscal cartilage that lines the inside of the knee joint. This type of Baker’s cyst is the most common. It is sometimes referred to as a secondary Baker’s cyst. In a secondary Baker’s cyst, the underlying problem within the knee joint causes too much synovial fluid to be produced within the joint. As a result of this, the pressure inside the knee increases. This has the effect of stretching the joint capsule. The joint capsule bulges out into the back of the knee, forming the Baker’s cyst that is filled with synovial fluid.
A Baker’s cyst often gets better and disappears by itself over time. However, it may persist for months or even years before it goes. In a lot of people it causes little in the way of symptoms and no specific treatment is needed. There are various treatment options that may help if you do have symptoms associated with a Baker’s cyst. These include: • Cryotherapy Ice pack therapy may sometimes be effective way of controlling the pain caused by Baker’s cyst. this may also help to reduce swelling and pain. Make an ice pack by wrapping ice cubes in a plastic bag or towel. (Do not put ice directly next to skin, as it may cause ice-burn.) A bag of frozen peas is an alternative. Apply the ice pack for 10-30 minutes. Less than 10 minutes has little effect. More than 30 minutes may damage the skin. • Support stockings - these provide compression and may help to reduce the swelling and the risk of a DVT. • Non-steroidal anti-inflammatory drugs (NSAIDs) – these can help to relieve pain and may also limit inflammation and swelling. There are many types and brands. You can buy ibuprofen at pharmacies without a prescription. You need a prescription for the others. Side-effects sometimes occur with NSAIDs. Stomach pain, and bleeding from the stomach, are the most serious. Some people with asthma, high blood pressure, kidney failure, and heart failure may not be able to take NSAIDs. So, check with your doctor or pharmacist before taking them, to make sure they are suitable for you. If the cyst ruptures, the fluid from inside the cyst may leak into the calf and cause worse pain. Stronger pain relief may be needed. • Crutches – it may be necessary to use crutches to get about until your symptoms ease. They help to take the weight off the affected leg while you are walking. • Physiotherapy – keeping your knee joint moving and using strengthening exercises to help the muscles around your knee may be helpful.
• Fluid drainage – sometimes your doctor may use a needle to drain excess fluid from your knee joint to help to relieve your symptoms. However, it is common for the Baker’s cyst to re-form over time. Cortisone (steroid) injection – this is sometimes used following fluid drainage, to reduce the pain and inflammation caused by the cyst. It does not prevent it from coming back again. • Surgery to remove the cyst – this is sometimes done, especially if a cyst is very large or painful and/or other treatments have not worked. Sometimes a keyhole method is used to close off the connection between the Baker’s cyst and the knee joint. The cyst is also sometimes removed using open surgery. Surgery may be carried out to treat an underlying problem at the same time – for example, repairing a meniscal tear.