Emerging Evidence On Treatment Of The Diabetic Charcot Foot
Essential Diagnostic Insights
The diagnosis of Charcot foot syndrome is primarily a clinical one. A hot, red, swollen foot in a patient with neuropathy is Charcot foot until proven otherwise. Clinicians must have a high index of suspicion.3 One can sometimes elicit a personal history of antecedent trauma. The patient usually recalls the trauma to be trivial. There is usually a temperature differential between feet of between 4 and 10ºF.4 One can obtain temperature measurements by contact dermal thermometer, non-contact infrared thermometer or by infrared thermography. Obtaining temperature measurements is the single most important test in our practices for uncovering inflamed Charcot feet.
The task force reviewed all the existing classifications for Charcot foot. We determined that while all the classifications are descriptive, none are particularly helpful in providing a prognosis of the condition or determining treatment.1,2 Therefore, the task force recommended a simple clinical classification based upon inflammation. If there is inflammation present, the Charcot foot will be active. When there is no inflammation, the Charcot foot will be inactive. These are better descriptors than acute and chronic since the latter only describes time or duration of the condition. One can discern active and inactive Charcot foot clinically, and help determine what treatment is best.
In regard to the initial presentation, X-rays may be normal, but subtle changes in bone quality or subluxations can be visible. If the syndrome progresses unfettered, frank dislocation and fractures occur. Medial calcification of the arteries can be visible on X-ray as a secondary finding. Magnetic resonance imaging (MRI) allows for the detection of subtle changes in the marrow and can be positive when the X-rays are normal.
Magnetic resonance imaging is not good at differentiating Charcot foot from osteomyelitis as both conditions appear similar.5 Even experienced radiologists have difficulty discerning between the two conditions. Looking for secondary signs can help one differentiate between the two. In regard to secondary signs, osteomyelitis primarily affects one bone while Charcot foot affects several bones and joints. Deformity is rare with osteomyelitis but common with Charcot foot. Osteomyelitis usually occurs in the toes, forefoot and heel while Charcot foot usually occurs in the midfoot and ankle. Other tests like nuclear imaging, positron emission tomography (PET) scans or sulfur colloid marrow scans are helpful in some cases.
The task force offered the diagnostic recommendations.1,2
• The diagnosis of active Charcot foot is primarily based on history and clinical findings. One should confirm the diagnosis with imaging.
• Inflammation, the earliest finding in Charcot, plays a key role in the pathophysiology of the Charcot foot.
• The occurrence of acute foot or ankle fractures or dislocations in neuropathic individuals is considered active Charcot foot. This is due to the inflammatory process of bone healing, even in the absence of deformity.
• X-rays should be the initial imaging. One should look for subtle fractures or subluxations if no obvious pathology is visible.
• In the absence of radiographic findings, MRI or nuclear imaging can confirm clinical suspicions.
What The Literature Reveals About Medical Treatment
The most important immediate treatment for the active Charcot foot is offloading. The use of a total contact cast immobilizes and offloads the foot.6 In certain settings, a removable cast walker would be appropriate. In some cases, we recommend total non-weightbearing.