Charcots Foot is a complication that occurs in those who develop a sensory neuropathy, most commonly in diabetes. A sensory neuropathy is a disorder of the nerves in which there is an inhibition of the nerves to sense things like pain. In diabetes the high blood sugar levels over a longer period of time damages the nerves to cause the neuropathy.
If there is some trauma or damage to the foot, then those with the sensory neuropathy will keep walking around on that damage as they do not feel the damage. This leads to subluxations and damage to the joints, most commonly a severe collapse of the arch of the foot, almost causing what is called a rocker bottom foot.
One way to think about is to to imagine that you sprain your ankle and do not feel any pain from it. As you feel no pain you keep walking around on that sprained ankle. It is not hard to imagine how much more damage is going to get done to the ankle joint and the ligaments around it by continuing to walk on it. We need the pain sensations to tell us to rest the ankle and get the weight off it so that it can heal up. Those with the sensory neuropathy in diabetes do not get those pain signals to tell them to get off the ankle and rest it. The first they may notice of the problem is when the see all the swelling and deformity of the ankle. This is what a Charcot’s Foot is.