Knee effusion is a condition where fluid accumulates around the knee joint. This is sometimes referred to as having a swollen knee or having “water on the knee.” Normally, our joints have a small amount of fluid surrounding them called synovial fluid. This helps to reduce friction and promote smooth joint rotation. However, there are instances where our joints accumulate extra fluid as a result of injury, infection, or due to a contributing medical condition.
Knee effusion and bone marrow loss
Knee effusions or water on the knee can harm the muscles and various structures of the knee over time. This may lead to thigh muscle to weaken and atrophy (shrink or waste away) if not treated promptly. Knee joint effusions are also associated with an increase in knee cartilage defects and bone marrow lesions, according to recent studies.
Researchers from the University of Tasmania in Hobart completed a cross-sectional and longitudinal analysis involving more than 900 participants affected by knee effusion. They found that knee effusions—particularly of the suprapatellar pouch—may be causally related to cartilage defects, which could subsequently lead to bone marrow lesions and cartilage loss over time. Higher grades of effusions were associated with an increased percentage of cartilage defects.
The average age of the participants was 62 years. All underwent MRI of the right knee and assessment of knee synovial effusion—synovitis to obtain a baseline. Contrast imaging using T2-weighted MRI was used to assess different regions of the knee, which included four sub-regions: the suprapatellar pouch, the central portion, posterior femoral recess, and subpopliteal recess.
By following participants over time, they found that suprapatellar pouch effusion was significantly associated with a change in total tibial and patellar cartilage volume. After 2.6 years of follow-up, the researchers discovered that effusions in this region were significantly associated with an increase in bone marrow lesions. All conclusions were adjusted for age, gender, body mass index (BMI). and radiographic osteoarthritis (OA).
Knee effusion (Water on the knee) treatment
There are a number of different causes of knee effusion. Some may be infectious while others have something occurring more acutely, such as a traumatic injury. The underlying cause of knee effusion will ultimately guide treatment.
For the most part, regardless of the underlying cause, non-steroidal anti-inflammatory drugs (NSAIDs) will be the most common medication prescribed to reduce swelling and pain associated with knee effusion. The use of corticosteroids is another class of drugs that may be utilized to help reduce these symptoms if NSAIDs are found to be insufficient.
Those affected by gout and pseudogout who become afflicted by knee effusion are often recommended to take colchicine, which helps to prevent gout flare ups. The use of NSAIDs and corticosteroid injections may also help with pain in these patients. Drugs such as allopurinol or probenecid help to lower the production of uric acid in the body.
In case of an infection causing fluid buildup, antibiotics can be used when first identifying the causative organism and removing the fluid buildup.
Arthrocentesis is a therapeutic procedure as well as serving as a diagnostic tool. Is the most accurate test for diagnosing the cause of knee effusion while at the same time helping to relieve pain. The procedure involves using a syringe to collect synovial fluid directly from the affected joint – also known as joint aspiration. Once this fluid is collected, it can be analyzed looking at color, clarity, viscosity, white blood cells, and polymorphonuclear leukocytes (PMN)—a category of white blood cells. Arthrocentesis has the added benefit of being quick and easy while inflicting minimal discomfort on the patient.
In severe cases of knee effusion where damage is beyond repair, joint replacement may be the only option.
Knee effusion (Water on the knee) home remedies and exercises
The following are some home remedies for water on the knee or knee effusions that can be done before getting professional medical attention.
Rest: Constantly putting stress on your knee joint will make it difficult for the healing process. Stress by simply standing for long periods of time can take a toll on weight bearing joints like the knees.
Cold therapy: This may be done by simply applying ice on the affected knee to help reduce pain and swelling. Using an ice pack is ideal, but ice cubes in a towel or a bag of frozen vegetables will also do the trick. It is recommended to ice the affected joint for about 15 to 20 minutes every two to four hours.
Elevate the joint: This can help relieve pressure on your knee joint and return blood to the upper part of the body. The general rule of thumb is to raise the knee higher than the level of the heart and support the leg with the use of pillows.
Use crutches or walking devices: This will help protect the knee and reduce the stress put on it through daily activity. Knee braces may also be utilized to a similar effect.
While the above recommendations are considered the initial conservative therapy for knee effusion, once the pain and swelling have gone down, performing strength and balance exercise can help ensure your knee has muscle support to reduce the chances of injury in the future. The following are some knee joint effusion exercises for injury prevention you can try today.
Wall squats: Done by standing with your back flat against a wall and feet far enough away so that they bend at the knees. You should look like you are seated but the wall is supporting most of your weight. hold this position for about 10 seconds, keeping your knees at hip width apart throughout the exercise. After 10 seconds, return to standing position and repeat.
Straight leg lifts: Start by lying on the ground with your left leg bent so that the knee is pointing towards the ceiling. Your right light should be lying straight along the floor. Now lift your right leg straight off the floor while engaging your stomach and buttock muscles. Only your leg midair for a few seconds, then repeat on the opposite side.
Balancing knee exercise: Using the support of a table or chair, lift one foot off the ground and balance yourself. Hold this position for one minute or as long as you can while keeping your back straight. Balancing exercises will help improve knee stability and reduce the chances of injury.
Knee effusion (Water on the knee) prevention
If you suffer from a long-term health condition like rheumatoid arthritis or osteoarthritis, you are more likely to develop knee effusion than those not afflicted by these conditions. It is recommended to maintain regular appointments with your doctor to keep track of your disease and to recognize any complications to help alleviate them in their early stages.
While performing exercises to strengthen leg muscles are a good idea, it is advised that at-risk individuals engage in exercises that do not put much pressure on the knees. These include swimming and water aerobics.
It is recommended that obese patients lose weight. Your doctor can help devise a weight loss treatment plan that works best for you and can provide encouragement and assistance when required.
There is a multitude of different causes of knee effusion and it is highly recommended to see a doctor right away. Depending on the level of inflammation, knee effusion can begin to degrade the knee joint further if not treated in a timely manner. By seeing your doctor, you can help mitigate any potential long-term effects and even prevent disability.