Charcot foot: protecting and rebuilding the collapsing foot

What happens inside a Charcot foot

In a numb foot, a minor injury you may not even notice can set off an outsized inflammatory reaction that switches on the cells that break down bone. Walking on the weakened foot can then loosen ligaments, break bones and pull joints out of place.⁠^[1] With little pain to make you stop, people may keep walking on it, and the arch can collapse into a curved “rocker-bottom” sole.⁠^[5]

While Charcot is active, the foot is warm and swollen and the bones are fragile. In remission, the inflammation has settled and any fractures have knit, with or without a lasting change in shape. Specialists say “remission” rather than “healed” because walking in ordinary shoes too soon can restart the process.⁠^[1,5]

Swipe sideways to see the whole drawing.

Charcot develops in people with neuropathy, especially long-standing neuropathy, and a tight Achilles tendon adds to the tendency.⁠^[5] Most have diabetes, though neuropathy from any cause can lead to it.⁠^[1] The Lower Extremity Nerve Institute has a guide to peripheral neuropathy (external site).

Early signs, and why days matter

Watch for one foot that feels warmer than the other, redness and swelling; soreness may be mild or absent because of the numbness.⁠^[5,1] A difference of about 2 °C (4 °F) between matching spots on the two feet has been used as a marker in several studies, read together with redness and swelling.⁠^[1] Early X-rays can look normal, and Charcot can resemble infection, gout or a blood clot.⁠^[1]

Catching it early appears to matter. In one small study of people with diabetes, 19 of 24 were first misdiagnosed, most often as a sprain. Of 11 people referred before fractures showed on X-ray, only 1 went on to extensive fractures and severe deformity, compared with 12 of 13 referred later.⁠^[6] Our guide to a red, hot, swollen foot explains how to tell them apart.

How we evaluate a warm, swollen foot

Dr. Ozturk compares the warmth and swelling of both feet, checks feeling and pulses, and looks for any opening in the skin. The guideline calls for X-rays first, ideally of both feet, and an MRI when those look normal but Charcot is still suspected. It suggests not relying on blood tests to confirm or rule it out.⁠^[1] We take X-rays and do noninvasive circulation testing at our practice, and arrange MRI at an outside imaging center. With an open sore, we also check whether infection has reached the bone; see how a foot wound is evaluated.

Protecting the foot while Charcot is active

This is the window for preventing collapse. The guideline recommends a non-removable knee-high device to hold the foot still and take pressure off it. A total contact cast is the suggested first choice and a knee-high walker made non-removable the second. The guideline also suggests avoiding shoes, sandals or casts that stop below the ankle, and using crutches or a walker to keep weight off the foot.⁠^[1]

At our practice, we apply a total contact cast or fit a knee-high device that stays on, and we show you how to get around safely. Because a cast can rub a numb leg, we check your skin at every visit: in one study cited by the guideline, 14% of people with diabetes treated in a total contact cast developed a new blister or ulcer from it.⁠^[1] See total contact casting.

Expect months. In a UK and Ireland audit of 288 cases, the median time to resolution was 9 months when non-removable offloading was part of the first treatment and 12 months otherwise.⁠^[2] From experience, the guideline’s authors suggest keeping up protection for four to six weeks after the signs settle, then moving into footwear gradually.⁠^[1]

Why an ulcer on a Charcot foot matters

When the arch collapses, pressure under the midfoot can rise and lead to an ulcer there.⁠^[7] Charcot by itself does not carry a high amputation risk; an ulcer is what multiplies it.⁠^[8] In a single-surgeon series of 280 Charcot feet in people with diabetes, a major amputation was needed in 21.3% of feet that arrived with a Charcot-related wound, compared with 4.5% of feet without one.⁠^[3] Keeping the skin closed is the aim of every treatment below; for wounds that have already opened, see diabetic foot ulcers.

When surgery is considered

Surgery can make a foot safe again when a cast or brace can’t. Even during the active stage, the guideline suggests considering an operation for unstable joints, a shape likely to cause an ulcer inside the cast or walker, or pain a cast can’t control. It advises immobilization first, to let the inflammation calm down.⁠^[1] Most ulcers under a collapsed midfoot can be managed with wound care and offloading; surgery becomes necessary when one fails to heal.⁠^[7]

Reconstruction can include shaving off a prominent bone, lengthening tendons such as the Achilles, or realigning and fusing joints.⁠^[1,3] As a Foot and Ankle Surgeon with board certification in wound care (FAPWH), Dr. Ozturk performs Charcot reconstruction and these related procedures for the feet that need them:

• Removing a bony prominence (exostectomy). If a bump of bone under the collapsed midfoot keeps an ulcer from healing, it can be shaved flat to take the pressure off. In one series of 27 of these operations, 74% of the ulcers healed, and most of the failures were under the outer edge of the foot.⁠^[7] See exostectomy.
• Realignment and fusion. The collapsed bones are realigned and fused in place with internal plates and screws, an external frame, or both, so the foot rests flat and shares pressure across the sole. No single way of holding the bones has proved superior.⁠^[1,4] See Charcot reconstruction and external fixation.

For carefully selected feet that might otherwise be lost, the results are encouraging. In the pooled review, the bones fused in 86.1% of reconstructed feet, 91% of people were reported to be walking again, and 5.5% needed an amputation afterward.⁠^[4] In the single-surgeon series, 90.0% of the 180 limbs that went on to reconstruction were saved.⁠^[3] Told your foot can’t be saved? A limb salvage second opinion can show whether reconstruction is still possible. Our sister practice, the Center for Lower Extremity Surgery, has a Charcot foot page (external site) focused on surgery.

Risks and limits

Charcot surgery is demanding. Complications include infection of the incision, a wound that opens, bones that fail to fuse, broken or loosened hardware and the need for more treatment.⁠^[1] In the pooled review, 36% of people had a complication directly linked to the surgical technique, and the authors rated the evidence as low quality, citing a lack of controlled studies, inconsistent reporting and varied patient selection.⁠^[4] See preparing for limb salvage surgery.

Living with a foot in remission

Once Charcot settles, the guideline recommends shoes and inserts shaped to fit and support your foot, to help keep it from flaring again. If the foot stays deformed or unstable, a custom below-knee brace adds protection; one design the guideline’s authors favor is the Charcot restraint orthotic walker (CROW).⁠^[1] Our practice offers therapeutic shoes and custom inserts, and the Ozturk Foot & Ankle diabetic foot care page (external site) has more on protective footwear. See offloading boots and footwear.

Charcot in one foot makes the other more likely to be affected, so check both feet every day, keep your blood sugar under control and keep up regular foot check-ups.⁠^[5] See keeping your foot in remission.

When to seek care

If you have diabetes or numb feet, call us the same day at 908-215-5953 when one foot turns warm, red or swollen or changes shape, even without pain. Keep weight off it until you’re seen. See us within a day or two for any foot wound that isn’t healing, especially if you have diabetes.