What is it?
In the late 1800’s, a French physician, Dr. J. M. Charcot, was the first one to describe the destructive changes he found in the joints of persons with decreased feeling in their legs and feet.
Today the term, Charcot joint, is used to refer to any joint in the insensitive foot that is destroyed or dislocated. The term, Charcot foot, is used to refer to a foot that has experienced many Charcot joints and has actually changed shape.
What Causes Charcot Joints?
The foot of a person, either with or without feeling, experiences small and sometimes large amounts of injury or trauma everyday as a part of normal walking. The difference between the insensitive foot and the one with normal feeling is that when injury occurs in sensitive foot, the person will stop walking to rest or protect the injured foot. Whereas, the person with the insensitive foot will continue to walk, which leads to further injury with possible bone and joint destruction. Also, the muscle strength in both the feet and the legs of a person with insensitivity is usually affected as part of the disease process. This leads to a muscle imbalance which affects the way a person walks and the way the foot functions. The foot will strike the ground harder during walking, resulting in greater force going through the bones and the joints, causing greater and more frequent injury. Twists or sprains of the foot and ankle are also more common and even though there has been significant injury, the person with insensitivity will continue to use the foot.
Another complication that occurs with the insensitive foot is a loss of muscle tone in the blood vessels that supply blood to the feet. This results in an increase in blood flow which has the affect of removing some of the minerals that help to make bones strong. The bones are thus weakened and more likely to break when placed under stress.
There is usually not a single event or large injury to the insensitive foot that causes fractures or destruction of the joints, but an accumulation of many small injuries that result in Charcot joints or a Charcot foot. Factors which will increase the chance of developing a Charcot joint include 1) the severity of the sensation loss, 2) foot or leg deformities that will put more stress on the foot 3) the type of work and the amount of time spent on the feet at work or at home 4) any activity or condition that puts increased stress on the feet, and 5) poorly supportive shoes.
What does this mean to you as a person with an insensitive foot?
It means that you need to be aware of the process and the possibility that it could happen to you. In the insensitive foot the pain that would stop a person with normal sensation is not present, so you need to be aware of the other signs and symptoms that will tell you that injury has occurred. If a bone has been broken or a Charcot joint has occurred you will have one or all of the following signs: 1) swelling (mild or great), 2) an increase in skin temperature in the area, 3) redness in the area and, 4) a lack of sweating resulting in dryness of the skin over the area.
It is important that you recognize these signs and understand their seriousness so that you will seek proper medical care quickly and stop the destructive process before it worsens.
Some patients will wait until a fifth sign appears, destruction and structural changes (the foot will appear shorter and wider). Some patients seek help only because their foot will no longer fit into their shoes. An untreated Charcot foot will develop a “rocker bottom” a shape much like a rocker on a rocking chair as the arch of the foot collapses and joints are destroyed.
The best form of treatment is prevention. This starts with patient education; making you aware of the process, what signs to look for and what outcome can be. The insensitive foot deserves special attention. This starts with regular visits to your podiatrist. It may require special shoe gear such as extra depth shoes with custom molded insoles or custom made shoes, if deformities are present, to cushion and protect the foot. It requires you or someone to visually check your feet each day because you cannot depend on sensation to alert you about problems or injuries.
If prevention fails and the signs like those described earlier appear, seek medical attention immediately to determine the seriousness of the problem. If a fracture has occurred, the treatment will be similar to the treatment of any person with a broken bone or joint. Healing will require protecting the foot from further harm. Forms of protection may involve any of the following: casts, crutches, wheelchair or bed rest. The treatment may last for months until healing is complete, even under the best circumstances.
Sometimes joint destruction is great enough to result in a permanent misshapened foot with bony bumps or prominences. This will always require special shoes. Sometimes, even surgery to fuse broken joints or remove bony prominences may be performed. Long term treatment primarily consists of prevention. If prevention fails, then the goal is to limit the amount of destruction and foot deformity that can occur.