Knee effusion

Knee effusion, commonly referred to as "water on the knee," is a medical condition characterized by the accumulation of excess fluid in or around the knee joint. This condition can result from various causes, including injury, overuse, underlying disease, or infection. Knee effusion can lead to pain, swelling, and reduced mobility, significantly impacting an individual's quality of life.

Causes

Knee effusion can be caused by a variety of factors, which are generally categorized into traumatic, non-traumatic, and infectious origins.

• Traumatic causes: These include injuries such as ligament tears, bone fractures, and meniscus tears. Trauma to the knee can lead to bleeding in the joint, resulting in a hemarthrosis (blood effusion).
• Non-traumatic causes: These are often related to medical conditions such as osteoarthritis, rheumatoid arthritis, and gout. These conditions can cause an increase in the production of joint fluid or synovial fluid, leading to effusion.
• Infectious causes: Infections such as septic arthritis can lead to knee effusion. This is a more severe cause and requires immediate medical attention.

Symptoms

The primary symptom of knee effusion is swelling of the knee. Other symptoms may include:

• Pain in the knee
• Stiffness and reduced mobility
• Warmth and redness around the knee area
• Difficulty bearing weight on the affected leg

Diagnosis

Diagnosis of knee effusion typically involves a combination of medical history review, physical examination, and imaging tests. During the physical examination, a healthcare provider may perform the bulge sign test or the balloon sign test to detect fluid in the knee joint. Imaging tests such as X-ray, MRI, and ultrasound can help determine the cause of the effusion and assess the extent of the condition.

Treatment

Treatment for knee effusion depends on the underlying cause. General treatment options include:

• Rest and avoidance of activities that exacerbate the condition
• Application of ice to reduce swelling
• Compression with a knee wrap or brace
• Elevation of the leg to decrease swelling
• Nonsteroidal anti-inflammatory drugs (NSAIDs) for pain relief
• Physical therapy to strengthen the muscles around the knee and improve mobility

In cases where the effusion is caused by infection or a significant amount of fluid is present, more invasive treatments may be necessary, such as:

• Aspiration, which involves removing the fluid from the knee joint with a needle
• Antibiotics for infections
• Surgery to repair any underlying damage or to remove inflamed synovial tissue

Prevention

Preventing knee effusion involves maintaining healthy joint function and avoiding injury. Recommendations include:

• Regular exercise to strengthen the muscles around the knee
• Maintaining a healthy weight to reduce stress on the knees
• Using proper techniques during physical activities to avoid knee injury
• Wearing appropriate footwear for activities

See Also

• Arthritis
• Joint effusion
• Synovitis
• Knee osteoarthritis