Fluid on the knee, frequently called water on the knee, is the term given to swelling on or around the knee joint. The swelling is usually caused by an accumulation of fluid that has built up in the knee. Fluid on the knee can be, but isn't always, chronic. There are many causes and many treatments.

Significance

The lining of the knee joint capsule, the joint around the knee, produces fluid that acts as a lubricant to the moving parts of the knee joint. It also nourishes the cartilage. Injuries and diseases can cause excess fluid.

Considerations

Water on the knee does not result only from excess fluid in the knee. Sometimes fluid can accumulate on the outside of the knee. This condition is called bursitis. When the swelling in on the back of the knee, the cause might be Baker's cyst.

Identification

The two most common causes of fluid on the knee are knee osteoarthritis and knee injuries. Injuries can be the result of overuse or a trauma to the area. Infections or inflammatory diseases are other common causes.

Symptoms

Swelling is not always visible. Pain may or may not be present. Inability to completely straighten the leg and difficulty walking, running or standing are symptoms. If an inflammation, an infection, or gout is present, the knee can be hot, red, and/or swollen.

Treatment

The first treatment for fluid on the knee is to treat the underlying condition. The fluid can be drained or aspirated. Shots of cortisone are also used. Other methods of treatment include anti-inflammatory medications and antibiotics, along with rest, ice, elevation and wrapping of the knee.

Warning

A doctor should treat and advise when water on the knee is present or suspected. Infections, not always visible, can be dangerous and require immediate care.

Source:

Big Knee Pain: Water on the Knee

CNN Health: Water on the Knee