Diagnosing Charcot Foot

Specialists at NYU Langone’s Diabetic Foot and Ankle Center are experienced in the diagnosis of Charcot foot. In this condition, multiple fractures and, possibly, joint dislocations occur in the foot and ankle. Without treatment, the bones may become irregularly aligned or may collapse, resulting in permanent changes in the shape of the foot.

People with Charcot foot also have peripheral neuropathy, which is decreased nerve sensation in the outer limbs. This type of nerve damage may prevent a person from feeling pain associated with an injury in the foot. Peripheral neuropathy is a common complication of diabetes, a condition in which the body has trouble regulating levels of blood sugar.

Not everyone with Charcot foot has diabetes. Nerve damage associated with Charcot foot can occur as the result of a variety of other conditions. But it is most often diagnosed in those who have peripheral neuropathy, as well as diabetes.

Symptoms and Signs

Symptoms and signs of Charcot foot are not always obvious, especially at first. Often, people with the condition can’t feel the pain or discomfort that would typically indicate a problem.

They may see redness or swelling in the foot, or they may notice that areas of the foot are warm to the touch. These signs mimic those of an infection but can indicate the presence of tiny fractures in the bones of the foot.

As the condition progresses, more serious deformity in the foot may be visible. Some people may notice changes in the shape of the foot, such as a flattening of the arch in the middle of the foot, or a tendency for the inside of the foot to turn upward and not lie flat on the ground. Charcot foot can occur in the ankle as well.

Early diagnosis is crucial to effective treatment. Continuing to put weight on an injured foot can prevent a fracture from healing and, over time, make the problem worse. If you notice redness, swelling, or warmth, or feel pain or discomfort while walking, you should see a doctor as soon as possible.

Having Charcot foot also increases the risk of an open sore called a foot ulcer. Changes in the shape of the foot resulting from fractures may cause friction between the foot and a standard shoe, causing blisters that can progress into ulcers.

Misalignment of the bones in the foot may also change the way body weight is distributed during movement. To compensate for a weakness, you may shift your body weight to other areas of the foot, adding pressure and increasing the risk of an irritation or blister.

Because a person with peripheral neuropathy has lessened sensation in the feet, a blister or cut can go unnoticed. Without treatment, even a small blister can become a serious wound within days.

Reduced blood flow to the feet—another common complication of diabetes—may prevent an ulcer from healing, and an ulcer may persist for weeks or longer. Chronic foot ulcers can be very difficult to treat.

If a wound becomes infected, it can travel to the bone and compromise the health of the foot. Very rarely, this may require the amputation of a foot.

To confirm a diagnosis of Charcot foot, NYU Langone doctors conduct a medical history, perform a physical exam, and evaluate the results of diagnostic imaging tests.

Medical History and Physical Exam

Your doctor asks when you first experienced pain, tingling, or numbness in the foot and when you first noticed a blister, cut, or skin irritation.

He or she also asks if you have any medical conditions, such as, or in addition to, diabetes. For example, osteoporosis is a common condition among postmenopausal women. It causes bones to become weak and brittle. In someone with peripheral neuropathy, this may increase the risk of tiny fractures in the foot that go unnoticed.

During a physical exam, a doctor evaluates your feet for changes in appearance that may indicate bone or joint damage. He or she also inspects the foot, toes, and toenails for blisters, cuts, scratches, or ingrown toenails.

You may be asked to stand and walk, so a doctor can assess how the weight of your body is distributed across the bones and joints of the feet. A limp may indicate structural damage.

X-Rays

Doctors use X-rays, which produce images of structures inside the body, to examine the foot’s bones and joints. An X-ray can reveal a bone fracture or joint dislocation related to Charcot foot, as well as any change in the shape, or alignment, of the foot.

MRI Scans

MRI scans use a magnetic field and radio waves to create computerized, three-dimensional images of soft tissues inside the body. MRI images can reveal inflammation, which may be a sign of infection. Inflammation may also indicate tiny bone fractures associated with Charcot foot.