This information is intended for patients of our services who have diabetes and have been diagnosed with (or are suspected to have) a condition called Active Charcot Foot Syndrome (commonly known as Charcot foot).
What is Charcot foot?
In some patients with neuropathy (usually due to diabetes), the bones of the foot become inflamed and soften. This results in changes in the shape of the bone from quite minor forces - just standing on the foot (weight bearing) or walking can generate enough force to allow the shape of the foot to change.
The commonest cause of the Charcot foot is diabetes, but it can occur in people who have a different cause of nerve damage. It is rare – and affects only about 1% of people with diabetes-related neuropathy.
Charcot foot can lead to gross deformity or ulceration of the foot. This deformity especially if associated with ulceration or infection may put patients at risk of requiring an amputation of the lower part of the leg.
The reason why this inflammatory process occurs in the foot in patients with neuropathy is unknown.
How will I know if I’ve got Charcot foot?
The early signs of Charcot foot are inflammation (swelling, heat and redness) in the affected area of the foot or ankle. These symptoms are very like those of an infection or an injury/sprain. The condition may be triggered by an apparently minor injury or foot surgery but, often, there is no obvious trigger.
Because of the nerve damage, it is not usually painful. Some patients may have ache or discomfort and some patients may have quite a bit of pain requiring pain killers. In most cases, only one foot is affected but rarely it may occur in both feet at the same time.
Who will help me look after my foot?
Your charcot foot will be managed by our specialist footcare team which include podiatrists, an orthotist, nurses including wound care specialists, and consultants who specialise in treating diabetes related foot problems.
How is it treated?
The only effective treatment is to reduce the weight on the foot (limit weight bearing) and ankle and prevent it from moving (immobilisation) until the inflammation has settled. This is normally done with some form of "plaster" cast or using a removable boot (a Vacopaed boot). The cast or boot reduces the forces on your foot. You may also be advised to avoid weight bearing using crutches or some other device. You will find more information on the Vacopaed boot and videos reminding you how to apply it here.
In the diabetes foot clinic, we will examine your foot, and may carry out some simple non-invasive tests, such as temperature, neuropathy and circulation tests.
You will be sent for an X-Ray of the affected foot. This is the best way to see if there are any bony changes to the foot. In some cases, you may be asked to have an MRI (Magnetic Resonance Imaging) scan. This will show areas of inflammation within the bone, which is the earliest sign of the condition.
The aim of the treatment is to prevent foot deformity whilst the inflammation settles. If there has already been some change to the shape of the foot, this is not reversible, and the aim of treatment remains to prevent any further deformity.
You will have regular appointments with the diabetes foot team to monitor your foot. At these appointments, the team will regularly check the temperature of your foot (and compare it to the other foot), as this is one of the best ways to monitor the progress of the inflammation.
If wearing a non-removable cast, the cast will be removed prior to your clinic visit, an xray may be performed and and will have a clinical assessment before the cast is reapplied. If you are using a boot, this should be removed for your xrays.
You should wear your boot at all times when walking and weight bearing - never walk or stand on your foot without your boot in place, even for a few minutes.
Infection of the foot in patients with Charcot foot is common. Because of the neuropathy, unrecognised skin lesions and minor trauma can lead to ulceration and deeper infection. Superficial wounds may only require regular dressings. Deeper or spreading infections will require antibiotics and regular wound dressings. Sometimes you may need to be admitted to hospital for intravenous antibiotics or other treatment. Please contact your podiatrist or the diabetic foot centre during regular working times, if you are concerned about any change in your foot between clinic visits. If the clinic is closed (over a weekend), you should contact your GP out of hours service or attend the hospital ED.
What is the outcome?
Once the inflammation settles down, if the shape of your foot has changed, you may require prescription footwear and insoles. This is because the changed shape may cause added pressure on the skin which overlies any bony prominences. This pressure will lead to a build of hard skin (called “callus”), which can break down and form an ulcer. Arrangements to have you assessed and your footwear supplied will be made via the clinic but this process may take some time. If you no longer need your boot, we will give you advice or other footwear that may be suitable while awaiting specialist footwear/insoles.
How long does the treatment take?
The course of the condition varies enormously between individuals. Some patients with low levels of inflammation who are treated early with immobilisation may settle within a few months. The average time spent in a cast is 9 months but treatment may extend for 18 months or more in some cases.
Will it come back again?
Charcot foot sometimes flares up again when the boot or cats is removed. Sometimes this is because it had incompletely resolved when the immobilisation was removed. The process may affect the other foot in about 30% of cases.
November 13 2020