Diabetic foot complications are unfortunately a common occurrence. Of the many complications with which diabetes afflicts the body, few can be as disabling and potentially devastating for the foot and leg as Charcot neuroarthropathy. Named for a nineteenth century neurologist, this devastating diabetic complication can cause spontaneous fracturing of the foot that can continue over the course of a few months. As suddenly as it begins, the process will suddenly end and the remaining bone fractures will fuse abruptly in the position in which they collapsed. It occurs in up to 5% of diabetics. The word neuroarthropathy refers to nerve-related joint disease. Numerous nerve-related causes have been suspected for this sudden disease, which can also affect non-diabetics with certain nerve diseases. One of two more popular theories believe that increased blood flow, due to disease of the nerves controlling the size of small blood vessels, washes away bone minerals. This results in bone that has less substance to it and can fracture more easily with little pressure. The other theory holds that poor sensation from nerve disease results gradually in too much focused joint pressure and eventually leads to destruction of the joint, which cannot sustain such pressure. Regardless of the actual cause, which is likely a combination of both the above theories, the end result of this disease is a devastating collapse of the joint involved. This can lead to numerous long term complications.

The part of the foot most commonly affected by Charcot neuroarthropathy is collectively called the tarsometatarsal joint. This is the general region of the connections between the long bones of the foot and the bones in the middle of the arch, and is not unlike the mass of bones in the palm of the hand and wrist. Another area commonly affected is the ankle joint. When the disease starts, the foot or ankle will suddenly become red, hot, and swollen. Pain may or may not necessarily be a part of the symptoms. It is all too frequent that this condition is mistaken for an infection by medical staff who don't see it regularly, as the appearance of the foot on exam and on x-rays can resemble a foot and bone infection. If a person who develops this continues to walk on the foot, the bone destruction continues and the joint continues to collapse irreversibly further. When the process ends a few months later, the collapsed foot or ankle will then fuse in that position. After fusion, the foot will be left in an abnormal position. In particular on the foot, the bones that were once part of the arch have collapsed into a concave position. This can create a number of long term complications. The skin on the bottom of the foot is not accustomed to the pressure from the bones pushing further down towards the skin, and the additional pressure from the ground below will cause the skin to callus in the middle of the foot as it protects itself from the increased pressure. This will eventually lead to a wound developing under this area of high pressure. Since fat padding is limited in the arch and the bone is brought even closer to the skin and wound surface by the joint collapse, bacteria on the wound can easily spread into the bone. Bone infection is a particularly serious complication, and the abnormal bone left after Charcot neuroarthropathy has ended can potentially harbor bacteria more easily. This has the potential to lead to a partial foot or below-knee amputation if the infection gets out of control.

All of these complications can be prevented without surgery if the disease is addressed quickly enough. Treatment started as soon as the first sign of disease appears can protect the foot or ankle from collapse. Without weight-bearing pressure, the fractured bone may not move or collapse to any great degree, and with proper treatment the anatomy of the involved joints can stay relatively intact. This requires strict non-weight bearing on the involved leg until the active fracturing phase of Charcot neuroarthropathy is over. The time required for this is usually at 3 months, but can be longer. The only way to effectively reduce the pressure is to hold the foot in a hard cast, and use either crutches or a wheel chair to assist in getting around. Even light pressure on the foot from standing on the cast can lead to bone collapse, so it is very important to keep strictly off the foot at all times.

The ability to walk can be drastically reduced if the collapse and resulting deformity of the foot or ankle is severe enough. Charcot of the ankle in particular leads to a significant walking disability, as the ankle becomes arthritic and poorly functional. Foot involvement is more common, and can lead to a dysfunctional surface upon which one walks on. The foot can become twisted off to the side, upward, or simply develop a rocker-style bottom shape. Special custom made shoes with specific molded padding must be used to support the foot and protect the skin from abnormal pressure, otherwise serious wounds can develop. If this is not enough, or if the deformity is too great, reconstructive surgery is needed to place the foot or ankle back into a semi-normal position. This surgery is difficult, time consuming from a recovery standpoint, and usually requires a device placed over the skin called an external fixator. The bones must be re-broken with precision and reset to restore proper positioning. Due to the Charcot disease, the bone material itself will be weaker and less able to hold more traditional internal screws and wires. Therefore, something else is needed to hold the bones in a corrected position until they heal. This has to be accomplished externally with a series of external wires driven into the bone and held together under tension with an external metal frame. This construction will keep the bones in the corrected position until they fully heal. Some surgeons advocate doing this even while the fracture phase of Charcot neuroarthropathy is occurring, without waiting for the bones to fuse from the initial fracturing. While this early intervention can limit the amount of deformity that occurs in the joints, it is very risky and can lead to more serious complications like amputation. It should be done by those with great skill and experience in addressing Charcot deformity during the active phase. Other treatments have been studied that attempt to reverse the bone loss seen in this condition, in a manner similar to the treatment of osteoporosis. The results so far do not translate well to real world application, and work remains on making this an effective early treatment for Charcot neuroarthropathy.

While Charcot neuroarthropathy can be severely disabling, it is very treatable if caught early enough, and the significant complications that result from the bone destruction can be reduced or even eliminated with skilled foot and ankle care.