Water on the knee is a broad term used to define excess fluid that gathers in or around your knee joint. Water on the knee is also referred to as a knee effusion. According to the American Association of Family Physicians, the causes of water on the knee include trauma, overuse or systemic disease (diseases that involve several organs or the entire body). Knee effusion can cause several obvious symptoms.
Knee effusion can result from activities that require repetitive starting and stopping at accelerated speeds such as tennis or football.
When traumatic injuries to the knees occur, excess fluid can build up in and around the joint. These injuries may include broken bones or fractures, ligament or meniscus (a disk of cartilage that acts as a cushion between the ends of bones that connect at a joint) tears and the general overuse of the knees.
If you're overweight your body places an extra burden on the knee joint when you walk. In time, your body will respond by producing a surplus of joint fluid.
According to the Mayo Clinic, osteoarthritis is the primary cause of knee problems. The condition causes joint cartilage to break down. Other underlying conditions that may cause knee effusion include rheumatoid arthritis, gout, pseudogout ( a form of arthritis), cysts and tumours.
The type of fluid that builds up in your knee depends on the underlying condition or the specific traumatic injury that prompted the excess fluid.
The symptoms of knee effusion may vary depending of the cause of the fluid build-up. In general the signs include pain and swelling.
When osteoarthritis is present, pain develops when bearing weight. It usually subsides with rest.
One knee may look bigger than the other and it may have a puffy appearance.You may also notice an obvious bulge around your knee.
If there is inflammation, the knee may be swollen, red and painful. If these symptoms appear suddenly, it could mean there's a bacterial infection in the knee joint.
Bruising & Stiffness
You may experience stiffness that makes it hard to bend or straighten your knee as far as you usually can.
When knee effusion is due to an injury, bruising may be present on the front, the side or the back of your knee. Attempts to bear weight on your knee joint may cause excruciating pain.
The treatment for knee effusion is based on the underlying disease or injury.
In the common case of osteoarthritis, excess fluid can be removed from your knee joint to help relieve pressure. Your doctor may inject a corticosteroid into the joint to treat inflammation.
Home remedies for knee effusion include applying ice to your affected knee for up to 20 minutes every few hours to help manage pain and swelling.
Over-the-counter pain medications such as NSAIDs (Advil, Motrin, others) are effective for diminishing both pain and inflammation.