The condition of Charcot (pronounced "Shar-Ko") foot is caused by an insensitive foot, that is to say a foot that has diminished sensation.
There are many reasons a foot may be insensitive. A traumatic nerve injury and hereditary insensitivity to pain are two examples. For centuries, however, the most common recognized cause of Charcot foot was infection. Tertiary (late-stage) syphilis and leprosy were the most frequent causes.
Today we don't see these conditions much, of course, but we do see a lot diabetes and alcoholism, both of which may lead to a peripheral neuropathy that may, in some cases, Charcot foot. In fact, diabetic and alcoholic neuropathy are the two most frequent causes of Charcot foot today.
The abnormal insensitivity of the foot that accompanies Charcot foot means that the foot will often begin to collapse, and the patient, insensitive to pain, cannot feel the pathology developing.
Treatment of Charcot foot typically involves complete non-weight-bearing immobilization of the foot during the acute phase, often followed by a combination of custom-moulded, accommodative orthoses, custom-moulded shoes (with specialized additions such as a "rocker bottom" to help roll the foot forward without taxing the damaged joints), and surgery to remove abnormal bony formations or to fuse unstable and arthritic joints.
Charcot foot is a serious condition, but with prompt recognition and treatment of the pathology, we are able to make the vast majority of patients return to productive function.