What is Water on the Knee?

Fluid is an important part of the knee’s design. Bending and rotation of the knee would be difficult without the natural fluid inside the joint. However, knee effusion, commonly known as water on the knee, is abnormal. It happens when excess fluid collects within the knee joint. There are various reasons that fluid builds up in the knee, which can result in a painful and debilitating state. All of the available treatments include removing the unnatural fluid, often in conjunction with medication.

Why Does Fluid Gather in the Knee Joint?

A swollen knee might be an indication that excessive fluid is present in the joint. In some cases, you may even be able to feel the liquid when you lightly press on the swollen area.

Like other problems associated with knee pain and swelling, trauma may have caused the fluid to build up in the knee joint. The knee’s response to trauma is to protect itself. The body will produce fluid that invades the space where the trauma occurred. This is often referred to as edema, to describe swelling that has resulted from fluid buildup.

One of the most common reasons for fluid build up is an arthritic joint. Rheumatoid arthritis is especially hard on knee joints, but can be successfully treated when properly diagnosed. Although medical science hasn’t defined the cause for rheumatoid arthritis, the symptoms have been defined and can include water on the knee.

Knee osteoarthritis is quite painful and can cause water on the knee. Osteoarthritis occurs when cartilage in the knee wears down over time, resulting in bone on bone friction. There is no cure for osteoarthritis, but the symptoms can be addressed.

If you have water on the knee that is accompanied with pain, stiffness, and fatigue, and the knee is warm to the touch, you might have rheumatoid arthritis. Rheumatoid arthritis and osteoarthritis are just two origins, but there are others.

Causes of Water on the Knee

• Infection (bacterial)

• Bursitis – bursae are small fluid sacs close to the knee joint. If the sacs become irritated and swollen, one result is water on the knee. An overworked knee joint is susceptible to bursitis.

• A compromised meniscus, or other tendons and ligaments around the joint

• Fractured bone. Even a hairline/stress fracture can have noticeable side effects.
• Injury – whether from repetitive stress or sudden trauma 

Treatment

As discussed above, water on the knee is a symptom of a separate condition. This means that the root cause must be addressed in order to combat the excess fluid.

The doctor will examine the problem knee to decide whether or not to remove the fluid. In some cases, diagnostic imaging may be necessary for a definitive diagnosis. To remove the fluid, the doctor will insert a long thin needle to withdraw the fluid from the knee, which will relieve pressure. The fluid is sent out for testing. What’s found in the fluid can help determine the type of treatment, as it may indicate the original problem that needs addressing.

Patients may expect any of the following.

• Anti-inflammatory medication

• Antibiotics to fight infection

• Arthroscopic surgery provides access to the inner knee without a large incision. It involves two small incisions; one to insert a small camera, and the second for instruments to repair the damaged joint.

• Corticosteroid to reduce inflammation. Corticosteroids are injected into the knee, or some can be taken orally.

Gone untreated, water on the knee can be very painful. Even after a needle aspiration, it is subject to recur if not treated quickly and properly. The best option for anyone suffering with water on the knee is to visit a doctor to find the origin of the effusion. Contact Advanced Bone & Joint today to schedule an appointment with our orthopaedic specialists. Call (636) 229-4222 today, or schedule an appointment online.