Home Health Water on the knee – just what is it anyway?
Water on the knee – just what is it anyway?
Written by Ken Chisholm, RN; BS; CNOR; CRNFA; OPA   
Thursday, 04 February 2010 15:24

I remember as a young boy, my mother telling me of occasions when my father would go the family doctor’s office to get treated for his “water on the knee” episodes. I never could figure out just what his problem was. All I knew was he went an had a needle placed in his knee and it was “drained.”

In an age where there was no World Wide Web, Google or WebMD, people would basically assign a term that they could associate with their problems to facilitate better understanding. Today, we have at our disposal more information that we can shake a stick at, but often still don’t quite understand what some conditions and symptoms really are.

As our population continues to age, more and more of us are experiencing the “joys” of aging, especially in our joints. That is not to say that the presence of “water” on or in a joint is merely from aging, because there are scores of causative factors…too many to discuss here.

All too often, people will come into an orthopedic specialist’s office complaining of a “soggy” feeling in their knee, frequently associated with a golf ball-sized “lump” in the back of the joint, which may be significant enough to restrict the extent of flexion (bending) of the knee. Many times I have heard, “When I awake in the morning, the knee is loose, but as the day progresses, the tighter and ‘fuller’ it feels.”

So, just what is this fluid buildup in the knee?

The medical term for this fluid accumulation is called effusion (e-fuze-shun). It describes the presence of, usually, an abnormally large amount of fluid within a joint, typically, but not limited to, the knee.

Those joints in our bodies that move and articulate, (coming in contact with another joint surface such as the knee, elbow, hip and ankle), are nourished to a large degree from normal fluid presence in them, called synovial fluid. It is produced by a membranous lining within the joint called the synovium. The fluid is predominately responsible for nourishment and lubrication.

When a joint becomes injured or inflamed, our bodies often respond to this internal irritation by producing additional fluid -its way of combating the irritation. As the irritation/inflammation persists or worsens, the fluid production increases. When production exceeds re-absorption, this excessive fluid (effusion) appears.

The more fluid that exists in the joint, the more difficult it becomes to move it, and the pressure of this buildup can become quite uncomfortable. Some of the types of irritation that can cause this buildup can include meniscus tears (also known as torn cartilage), arthritis, occasional reactions to injectable materials and fractures involving the joint cartilage, creating an uneven surface thus increasing friction.

How do you treat it?
Identifying the cause is the first, and usually, most important step. Knowing what is causing the effusion will go a long way in determining what needs to be done to reduce or eliminate it. In cases of meniscal cartilage tears, arthroscopic removal of all or part of the meniscus is usually indicated. In cases of arthritis, depending upon the type and severity, treatments can include anti-inflammatory drugs, cortisone injections, “gel” injections and often times, surgical intervention. To reduce the abnormal amounts of fluid production, one must find and eliminate the offending cause(s). Many times this can be easier said than done.

If I have these symptoms, what should I do?

First, check with your doctor. He/she can usually perform tests and examinations to diagnose the cause(s) of this effusion. Many times this can be treated by the family practitioner. In cases where more definitive treatment becomes necessary, you may ultimately be referred to an orthopedic surgeon for such things as gel or steroid injections, and possible surgical intervention such as outpatient arthroscopy.

The important take-home message is that, while some level of fluid present in a joint like the knee is normal and beneficial, excessive amounts that become bothersome to you are signs that something more is going on in there, and needs attention.

So, if your “soggy” knee is throbbing and bothering you, and you are having increasing difficulty bending it, and it feels “full” and you have a golf ball-sized bulge in the back of the knee, it’s time to get it checked out before it becomes any worse.

Chisholm’s expertise in nursing, orthopedics and surgery spans more than 30 years. He holds multiple national certifications in these specialties. His goal is to empowering people through education and information to become more engaged, proactive and responsible in their orthopedic health, and health care. For additional information on orthopedic-related topics, visit Ken’s Web site at Submit questions or comments to Ken at This e-mail address is being protected from spambots. You need JavaScript enabled to view it or at his Web site.



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