What is Charcot foot and why is it so serious?

Acute Charcot foot is a rare, but extremely serious condition of the feet that can lead to the destruction of bones and joints, resulting in deformity, loss of function, pressure ulcers, deep infection and, ultimately the need for amputation.

We sat down with Mr Arshad Khaleel, leading consultant trauma and orthopaedic surgeon based in Chertsey & Weybridge, to find out more about this dangerous foot condition.

What is Charcot foot and what are the causes?

The exact mechanism remains unknown, but there is a temporary increase in blood flow in the limb which produces swelling and skin redness. Shunting of blood through the bones leads to temporary osteoporosis, resulting in fractures and typical bone and joint destruction. The temporary increase in blood flow lasts about four to six months.

Although it is rare, it is possible to develop recurrent acute Charcot foot, and whilst the foot is the commonest location, any bone or joint may be affected.

What are the risk factors?

There are some known risk factors which include:

• long-standing diabetes
• poorly controlled diabetes
• loss of sensation
• injury

What are the symptoms of acute Charcot foot?

In the majority of patients, the condition is painless and hence, a diagnostic challenge. The most consistent feature is sudden swelling of the foot and possibly the leg. Typically, the patient is still able to walk, and describes the phenomenon of bone failure as “crunching” - an obvious deformity of the foot results. If the patient continues to walk, the deformity worsens and ulcers may develop.

How is it diagnosed?

The diagnostic challenge is to identify the condition before any foot collapse or deformity occurs. If the condition is identified at an early stage (pre-collapse) and appropriate treatment is introduced, it is possible to avoid developing any deformity.

The most useful test currently available is one that can demonstrate a rise in the shin skin temperature (compared to the other shin) and a reversal in the foot-shin temperatures. Normally, as the foot is further away from the heart, its skin temperature is lower than the shin; however, in acute Charcot, the foot temperature is typically three degrees higher than the shin temperature.

It is very common to confuse acute Charcot with cellulitis or infection, and it is extremely common to find patients placed on antibiotics during this early swelling phase. Once the foot bones start to collapse, fractures may be identified, but unless the shin and foot temperatures are measured, the acute Charcot phenomena may be missed.

How is acute Charcot foot treated?

Once the acute Charcot is recognised, the treatment is almost an emergency, especially if the foot has not collapsed.

The most important and simple measure would be to stop weight-bearing and refer the patient to a diabetic foot multidisciplinary team. The management offered by this team has demonstrated a dramatic improvement in outcomes, and in particular, a significant reduction in amputation rates. The team usually consists of an endocrinologist, vascular and orthopeadic surgeons, a podiatrist, radiologists, occupational therapists, and specialist nurses.

In acute Charcot foot, diabetes needs to be controlled, and the usual treatment is total contact casting. This involves using a plaster moulded to the leg and foot which distributes foot pressures uniformly, thus preventing focal pressure points. Once the plaster goes on, the swelling typically recedes dramatically and a review in a week is then carried out, which is crucial.

Is surgery needed?

Further X-rays are necessary during the initial period of casting, as in a small group of patients, the total contact cast is unable to maintain the shape of the foot and prevent collapse. Surgical treatment in this small group may be necessary to prevent continued collapse. Generally, surgery is avoided in the acute Charcot phase unless this is noticed.

The total contact casting is continued until the shin and foot temperatures return to normal. From my experience, this can take between four to six months.

How can it be prevented?

While there is no single measure to prevent this rare condition, good diabetes control and regular foot care are important.

Perhaps the most important message is educating the patient and caregivers that if a patient with diabetes suddenly develops swelling of the foot it is crucial that they are assessed for acute Charcot.

To make an appointment with Mr Arshad Khaleel, visit his Top Doctors profile and check his availability.