Water on the Knee

What is Water on the Knee?

Water on the knee is a common term for what doctors know as knee effusion. It’s a particular kind of swollen knee. It happens when you have fluid buildup around the knee.

Water on the knee, water effusion, and knee pain

You need a certain amount of fluid in your joints where bones come together. The fluid provides a cushion that enables you to move smoothly and without discomfort. But you can have too much of a good thing. When you have too much fluid, you get the swelling we call water on the knee, and the water effusion starts hindering your ability to bend and move the knee without pain. It’s also likely to make one knee look puffy and bigger than the other.

What Causes Water on the Knee?

Various conditions can produce a knee effusion.

Osteoarthritis and Water on the Knee

Often associated with aging, OA is wear and tear that deteriorates the cartilage in the knees (or other joints.)

Rheumatoid Arthritis and Water on the Knee

RA is an inflammatory response that can appear at any age. It usually manifests in the knees, hands, and/or feet and produces stiffness, swollen joints, and pain.

Infectious Arthritis and Water on the Knee

Infectious arthritis results from a viral, bacterial, or fungal infection in the joint. Sometimes the infection begins elsewhere in the body but migrates to a joint like the knee.

Psoriatic Arthritis and Water on the Knee

Psoriasis is a skin condition in which the skin forms dry, scaly, itchy patches. About 30% of psoriasis sufferers also develop psoriatic arthritis.

Gout and Water on the Knee

Gout is a particular kind of arthritis. A gout attack generally comes on suddenly and brings redness, swelling, warmth, and sever pain. Gout typically attacks a single joint although this is not universally the case. It results from the buildup of crystalized uric acid deposits in a joint.

Joint Injuries and Water on the Knee

Joint injuries are a very common cause of water effusion. They encompass injured or torn muscles, ligaments, and tendons and often result from sprains, strains, fractures, dislocations, tendonitis, or bursitis.

The body can respond to all these conditions with knee effusion because it’s attempting to prevent further damage by providing additional protective fluid to the knee.

Symptoms of Water on the Knee

As noted above, the symptoms of any knee effusion are likely to include swelling, reduced mobility, and pain. Beyond that, though, the symptoms may vary depending on the source. If osteoarthritis is the underlying cause, you’ll likely feel pain when you put weight on the knee, and the pain will probably subside when you rest. If you have water on the knee due to a joint injury, you’ll probably see some bruising, and putting weight on the knee can produce truly agonizing pain.

Avoiding Water on the Knee

Naturally, you’d rather not get a knee effusion if at all possible. You can improve your chances by losing weight if you’re overweigh or maintaining a healthy weight if you’re not. Being overweight puts more strain on your knees and makes injury more likely.

Avoid jolting movements, and don’t run on rough surfaces. Consider exercises and sports that are relatively easy on the knees. Such exercises include shallow (not deep) knee bends and straightening movements performed with most of your weight on the outsides of your feet. Knee-friendly sports include baseball, cross-country skiing, skating, cycling (in low gear with the seat high and avoiding hills), swimming (with flutter kicks and the knees straight), and walking.

In contrast, these sports are rough on the knees and possibly best avoided if you have concerns about the strength of your knees: football, rugby, hockey, sprinting, volleyball, basketball, squash, downhill skiing, jogging, and tennis. Essentially, anything that pounds or twists your knees.

The basic principle is to choose activities that are a good fit for the strength and capacity of your knees.

Sadly, though, even if you’re sensible, you might still end up with water on the knee, in which case, you’ll need medical treatment. Such treatment begins with diagnosis.

Diagnosing Water on the Knee

Diagnosis begins with a comparison between the swollen knee and the healthy one and then is likely to proceed to imaging with X-rays and/or magnetic resonance imaging (an MRI.)

Joint aspiration will come into play as well. Joint aspiration means that your health care professional uses a needle to extract fluid from the knee. The fluid yields measures of cell count, is cultured for bacteria, and checked for crystal deposits.

Your doctor may order blood tests as well. If so, he or she is looking for markers like white blood cell count and erythrocyte sedimentation (the latter detects inflammation linked to illness like infections, cancers, and autoimmune diseases.) Tests for levels of uric acid or C-reactive protein can provide indicators of a systemic inflammatory state possibly arising from a cardiovascular issue like coronary atherosclerosis or atherosclerotic cardiovascular disease.

Once your physician has determined for a fact that you have water on the knee and understands what’s causing it, treatment can begin.

Treating Water on the Knee

You likely already had your knee aspirated as a part of diagnosis. Joint aspiration will probably be part of your treatment as well. Since the water effusion is the buildup of too much fluid on the knee, you want to get rid of the excess. Once it’s drained, further therapy can begin.

Traditionally, addressing the underlying cause of water on the knee has sometimes involved surgery, steroid injections and other medications that come with a level of risk, and lengthy, painful physical therapy. Today, however, the form of regenerative medicine known as stem cell therapy is bringing relief to many. Stem cell therapy is minimally invasive, involves minimal risk, and can produce results quickly by accelerating the healing process.