What Causes Fluid in The Knee?

Fluid on the KneeA few weeks ago a friend asked me to write about what causes fluid in the knee. I’m usually happy for topics, as I don’t always have one in mind. This is an interesting one, since it is something people often complain about, or through observation, it  is noticed. Some persons say it is definitely since they started suffering with arthritis, others tell tales of that dreaded sports injury, or after a surgical procedure. Reality is there are varied reasons that lead to fluid retention.

When excess fluid accumulates in the knee or surrounding area, it’s knee effusion, commonly known as water in the knee.

 Signs and Symptoms

In persons with osteoarthritis, pain occurs when bearing weight. With arthritis there may be periodic inflammation, which can be due to the formation of bone spurs (osteophytes) or extra fluids in the knee. Swelling may be more pronounced after a long period of inactivity, such as when you first wake up in the morning. The skin on your knee may look red or feel warm when you touch it. In time, you may experience chronic inflammation of the knee that doesn’t get better with over-the-counter medications or anti-inflammatory drugs. One knee may appear larger than the other. Puffiness around the bony parts of the knee appears prominent when compared with the other knee. When the knee joint contains excess fluid, it may become difficult to bend or straighten the knee in certain cases.

Swollen Knee Vs Normal
Swollen Knee Vs Normal

If someone has injured their knee, they may note bruising on the front, sides, or rear of it. Bearing weight on the knee joint may then be impossible, and the pain unbearable. There could also be an underlying disease or condition. The type of fluid that accumulates around the knee depends on the underlying disease, condition or type of traumatic injury that caused the excess fluid. The swelling can, in most cases, be easily cured.

CausesFluid caused by Osteoarthritis

Engaging in high-risk sports that involve rapid cut-and-run movements of the knee, football or tennis for example, means an individual is more likely to develop water on the knee. Certain diseases and conditions are also contributors. As well, in overweight or obese individuals, the body places more weight on the knee joint. This causes more wear in the joint, and over time, the body will produce excessjoint fluid.


A sudden, one-off, injury to the knee, for example – a fall on, or direct blow tothe knee. Recurrent minor injury to the knee, or damage to any part of it can cause the painful build-up of excess joint fluid. Examples of contributory traumatic injuries are:

-Broken bones
-Meniscus tear
-Ligament tear
-Overuse injuries

Diseases and conditions

Underlying diseases and conditions include:

-Rheumatoid arthritis
-Bleeding disorders


If left untreated, water on the knee can severely limit your mobility. If the swelling is caused by an infection, it can destroy the joint.

Tests, Diagnosis and Treatment

Tests/scans show the inside of your knee joint. These listed can help determine whether there is fluid within the joint, or in a bursa, and what is causing the fluid to accumulate:

-X-ray – Your doctor may request an x-ray to make sure you haven’t broken or dislocated any bones, or to determine if you have arthritis.
-Ultrasound – This non-invasive imaging test is widely used to evaluate joint pain and swelling. It can be used also to diagnose arthritis or tendon/ligament disorders.
-MRI – If your history, examination and x-rays don’t identify the cause of your swollen knee, you may need an MRI. This test can detect tendon and ligament injuries that aren’t visible on X-rays.
-Blood tests – A sample of blood taken from your arm can be tested for evidence of:

o   Infection

o   Inflammation

o   Rheumatoid arthritis

o   Lyme disease

o   Bleeding disorders

o   Gout

-Joint aspiration – During this procedure, your doctor withdraws fluid from inside your knee to check for the presence of:

o   Blood, which may stem from injuries or bleeding disorders

o   Bacteria, which may be causing an infection

o   The crystals common to gout or to pseudo gout.

-Arthroscopy – An orthopaedic surgeon inserts a small, lighted tube with a magnifying lens (arthroscope), through a small incision in your knee and examines the inside of your knee joint.
-Joint replacement – If bearing weight on your knee joint becomes intolerable, your doctor may refer you to an orthopaedic surgeon for knee replacement.

Home Treatments

Taking care of yourself when you have water on the knee includes:

-Rest – Avoid weight-beUse RICE Therapy for  Home Treatmentaring activities as much as possible when your knee is painful and swollen.

-Ice and elevation – Cold therapy can help control pain and swelling. Apply ice to your knee for 15 to 20 minutes every two to four hours. You may use a bag of ice, frozen vegetables or an iced towel cooled down in your freezer. When you ice your knee, raise your knee higher than the level of your heart, using pillows for comfort.

-Pain medication
– Over-the-counter drugs may help relieve your knee pain. If you need something stronger, ask your doctor about prescription medications.

Your feet mirror your general health . . . cherish them!

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