Charcot foot is a progressive degenerative condition that affects the metatarsal, tarsometatarsal, and tarsal joints in the feet. Nerve damage (neuropathy) often accompanies this deformity and decreases the body’s ability to sense pain. As a result, the joints in the feet are subjected to repeated trauma and injury, causing progressive damage to the ligaments, cartilage, and bones.
Incidence and Prevalence
It occurs at the same rate in men and women and develops in both feet in approximately 20% of cases.
Charcot foot occurs most often in people with diabetes mellitus. According to the American Diabetes Association, 60-70% of people with diabetes develop peripheral nerve damage that can lead to Charcot foot and about 0.5% of these patients develop the condition. Typically, onset occurs after the age of 50, and after the patient has had diabetes for 15 to 20 years.
Signs and Symptoms
The progression of Charcot can occur in a matter of weeks or months. Minor trauma, such as twisting the foot, can initiate the process and the loss of pain perception and the sense of foot position can result in repeated joint injuries. Also, increased midfoot pressure due to a tight heel cord can result in a deforming force leading to joint breakdown.
Symptoms of Charcot foot include the following:
- Insensitivity in the foot
- Instability of the joint
- Strong pulse
Subluxation initiates the process of degenerative joint disease (arthropathy).
Deformity of the foot is caused by joint displacement and/or dislocation which may include bone fractures. If not stabilized the altered joints may lead to osteophytes protruding from the top or bottom of the foot as the body forms new bone to replaces bone loss.
Fractures may cause the tarsal bones to collapse, resulting in an outward bowing of the arch (called “rocker foot”).Complications of Charcot foot include calluses and ulcers, which occur when bony protrusions rub inside the shoes and may become infected.
Diagnosis is based on medical history (i.e., history of diabetes), symptoms, imaging tests (e.g., x-rays, MRI).
X-rays are used to detect joint effusions, osteophytes, fractures and joint misalignment and/or dislocation.
The goal of treatment is to stabilize the affected joints. Limiting the amount of weight on the foot for at least 8 weeks may help to prevent further damage. Offloading modalities including casting, walking boots or rolling walkers are typically used.
Surgery may be necessary to treat severe deformities and re-establish a stable construct. Also, recurring ulcers, often caused by bony prominences, are contoured to allow skin healing.
After treatment most patients with Charcot foot can resume regular activities but should be monitored to insure reoccurrence does not occur.