A fluid filled cyst or small sac that forms behind the knee joint is referred to as the Baker’s Cyst. It is also named as Popliteal Cyst. This condition occurs when the joint functioning is hampered due to an internal cause such as damage to the soft tissue structures, Arthritis etc. Such conditions provoke excessive synovial fluid development within the joint which tends to get stored in a soft tissue sac resulting in the formation of a cyst. In normal conditions, the synovial fluid helps to reduce friction between the constituent bones and makes it feasible for us to flex, rotate and move the legs and the knee. However, excessive build up can cause some discomfort which may require immediate medical attention.
Causes
- Knee injury may alter the flow and distribution of fluid in the joint
- Osteoarthritis
- Rheumatoid Arthritis
- Damage caused to the joint cartilage
Symptoms
- Pain while flexing the knee
- Tightness due to the fluid accumulation as the skin around the joint also stretches
- Swelling or inflammation at the back of the joint
- In case the fluid filled sac breaks and the fluid outflows into the lower leg, redness and inflammation may occur in the lower extremities
- Visibly prominent bulge behind the knee
- Some patients may feel as if water is running down their legs
- Inflammation in the calf area
Diagnosis
- The affected joint and leg are observed in detail and the patient may be questioned about the symptoms, past injuries and the onset of the condition
- MRI test may be required for detailed view of the knee joint and the affected soft tissue structures
- X-ray imaging may be done
- Ultrasound testing may be suggested
Treatment
- The cyst tends to dissolve on its own over the time in most cases. If the symptoms persist or get aggravated, the following methods may be adopted.
- Draining the excess fluid using a needle which is referred to as Needle Aspiration
- Ice therapy may provide relief
- Injecting steroids into the joint to reduce inflammation and pain
- The knee may be wrapped in a removable bandage for slight compression and support
- Weight bearing should be avoided for some time and use of crutches or a walker may be recommended
- Some pain killers and anti inflammatory medicines may be prescribed
- Maintaining a healthy body weight to avoid stressing the joint may be recommended
- Gentle exercises that promote range of motion may be incorporated in the daily schedule
- In case the underlying cause is a cartilage tear, surgery may be required to treat it
- Physical activity needs to be avoided for some time and the affected joint should be given adequate rest
