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What Causes Fluid on the Knee?

Meshell Powell
Meshell Powell

Fluid on the knee is a term used to describe swelling on or around the knee. This condition sometimes causes pain or discomfort, and the swelling may or may not be noticeable. Common causes of fluid on the knee include arthritis or traumatic injury involving the knee. Treatment for fluid on the knee depends on the direct cause of the swelling and may involve the use of over-the-counter or prescription medications, lifestyle changes, or surgical intervention.

A type of arthritis known as osteoarthritis is the most common cause of fluid on the knee. Osteoarthritis is a type of degenerative disease that causes the joint cartilage to break down. Symptoms may include pain, stiffness, or a feeling of warmth. Treatment for osteoarthritis typically includes the use of over-the-counter pain medications, heat therapy, and exercise.

A close up of the knee, with the ligaments in pink.
A close up of the knee, with the ligaments in pink.

Gout is another form of arthritis that may cause fluid on the knee. Gout occurs when uric acid builds up in the joint, triggering inflammation. In addition to pain and swelling, the affected joint often feels warm and may appear reddened. Treatment for gout includes the use of over-the-counter or prescription medications aimed at reducing pain and inflammation. Some doctors may also recommend dietary changes or an increase in fluid intake.

A diagram of the knee, including ligaments.
A diagram of the knee, including ligaments.

Rheumatoid arthritis is a disease of the joints that is believed to be caused by a faulty immune system. Symptoms often include pain, swelling, and weight loss. Rheumatoid arthritis treatment usually involves the use of a combination of prescription drugs, although surgical intervention may sometimes become necessary.

Traumatic injury involving the knee may lead to the accumulation of fluid on the knee. This is most common in sports-related injuries, although other factors, including automobile accidents or severe falls, may also be responsible for the development of this symptom. Treatment in this cases depends on the severity of the injury. Medication or lifestyle changes may sometimes provide sufficient symptom relief, although surgery is particularly common when fluid on the knee is caused by some sort of traumatic injury.

Fluid on the knee describes swelling on or around the knee.
Fluid on the knee describes swelling on or around the knee.

Any time a patient begins to experience possible symptoms of fluid on the knee, such as pain or swelling, a doctor should be consulted. In order for the proper treatment to begin, an accurate diagnosis should be obtained. Rest and the use of medications are able to reduce the inflammation in many cases. Sometimes, injections directly into the knee are helpful in treating this condition. In other situations, the excess fluid may be able to be drained from the knee.

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    • A close up of the knee, with the ligaments in pink.
      By: Alexandr Mitiuc
      A close up of the knee, with the ligaments in pink.
    • A diagram of the knee, including ligaments.
      By: Alila
      A diagram of the knee, including ligaments.
    • Fluid on the knee describes swelling on or around the knee.
      By: Maridav
      Fluid on the knee describes swelling on or around the knee.