Ballert Orthopedic :: Newsletters and Articles

Orthotic Management of the Charcot Foot
by Steve Galluzzo, CO April 2001

There are an estimated 16 million people in the United States with diabetes. Of these, as many as 40% of them have some degree of neuropathy. This disease often leads to Charcot foot and ankle deformities and continues to pose a challenge for physicians in terms of diagnosis and treatment. This is a condition of acute or gradual onset and, in its most severe form, causes significant disruption of the bony architecture of the foot. In this article, I focus on some of the critical aspects of recognizing and diagnosing this condition, as well as to some of the more prevalent and effective orthotic treatment methods.

Charcot deformities of the foot and ankle commonly affect patients with diabetes mellitus. It has also been associated with chronic renal disease, myelo-eningoule and alcohol abuse. It is thought that joint destruction in Charcot deformities is caused by a lack of protective sensation which renders those affected insensitive to paint and proprioception. This cumulative and repetitive uncensored trauma destroys the joint and causes fractures or dislocations that tend to abnormal biomechanical stresses to the foot. This process is brought on by an initial slip or trip causing a fracture that may or may not be perceived by the patient, but nevertheless almost always goes undetected until it is too late.

The acute stages of the Charcot process include warmth, erythema and swelling. Pain is usually absent due to the neuropathy, but is still a possibility if the sensory loss is not complete. Any such pain would also be much less than expected given the clinical and/or radiographic findings. Isolated unilateral swelling of the lower extremity, especially the foot, in the diabetic patient is another warning sign of this disease.

The exact etiology of the Charcot process is unknown. However, bony destruction, fragmentation, joint subloxation and bony remodeling are considered radiographic landmarks of this disease. These radiographic changes take time to occur, and may not always be evident at the onset of the process. But if suspected, treatment should begin right away. The proper treatment for a hot, swollen foot in a patient with sensory neuropathy is immobilization. When done properly, the best form of immobilization is total contact casting or various forms of solid ankle AFOs.

Charcot foot on the right foot of a patient with diabetic neuropathy. Note swelling and the presence of callous formation on the right foot.

Once diagnosed, patients are usually referred to an orthopedist, a podiatrist or a specialized diabetes foot center. The standard of care has become strict immobilization of the foot and ankle in an attempt to stabilize and protect the foot from further deformity. Strict non-weight-bearing measures are recommended by some diabetes foot centers. Some facilities are set up to provide total contact casting, but as an orthotic and prosthetic facility, we provide rigid custom orthoses for both healing purposes and definitive post-treatment use.

Total contact casting requires visits to the clinic every one to two weeks for cast changes, dressing changes and cutaneous inspections. Frequent X-rays are taken and the process can last anywhere from three to six months or longer.

An acute Charcot foot with characteristic swelling and arythema.

Alternative methods are orthotic management. Charcot Retaining Orthotic Walkers (CROW) have been used for many years and allow the patient some flexibility. The CROW is a castlike boot that completely encloses the foot and ankle and is made custom to the individual patient for ultimate total contact and pressure relief. The boot has a bivalve (two-piece) costruction with a soft plastazote liner and a rigid outer polymer shell. The outer sole has a Solid Ankle Cushion Heel (SACH) and rocker bottom that are necessary when immobilizing the ankle. This, as opposed to a Total Contact Cast, allows the patient to remove the orthosis while at home for bathing and daily dressing changes if necessary.

Neuropathic ulcer in a patient with Charcot-related foot deformity

Once the Charcot process has subsided and all wounds are healed, the lifelong protection of the at-risk foot begins. For the milder cases, custom-molded foot orthoses are used. They are fabricated from materials of different densities. Among those are plastazote, nickleplast, poron, puff and cork. They are fabricated with the less-dense materials over the sensitive areas and the denser materials around those same areas to provide support and protection to the affected foot. In some cases even a custom molded shoe would be necessary to effectively manage the unshapely foot and mid-foot deformity

For those patients who suffered the most subluxation and mid-foot collapse, a Patellar Tendon Bearing (PTB) AFO may be the only answer to stop any recurrences of plantar surface ulcerations. This is an orthosis that combines custom insoles, custom shoes, rigid rocker bottom shoe modification and prosthetic engineering techniques to help redistribute the paitent’s mass to areas other than the plantar surface of the foot. It subtly transfers the patient’s body weight from the bottom of the foot to the gastrocnemius muscle and the patellar tendon. By eliminating motion at the ankle complex and with the addition of the rocker bottom, the orthosis reduces the sheer forces and stresses that are responsible for the recurrence of diabetic ulcerations.

Patellar tendon bearing orthosis with custom molded shoe and rocker bottom sole.