Charcot foot

What is Charcot foot?

In Charcot foot, the bones of the foot or ankle become weak and can fracture and dislocate, usually without the pain that would normally make you stop walking. Because sensation is reduced, people continue to walk on the injured foot, and the damage progresses. Over time the arch can collapse into a “rocker-bottom” shape.^[1,2]

It occurs in people with neuropathy — most commonly long-standing diabetes — and a tight Achilles tendon may add to the risk.^[1] International guidelines separate the active stage, when the bones are inflamed and fragile, from later stages, when the foot has healed in whatever shape it ended up.^[3]

Symptoms

The early sign is a foot that is warm to the touch, red and swollen, often with only mild soreness or discomfort. Because the foot is numb, some people have no pain at all.^[1] Charcot foot in someone with diabetes should be suspected whenever a foot is warm, swollen and red without an obvious cause. It can look like an infection or a sprain, and it can coexist with an ulcer, so an experienced evaluation is important.

How it’s evaluated

The examination compares the temperature and swelling of the two feet, checks sensation and circulation, the shape of the foot and any ulcer. X-rays are the first imaging test, and MRI or other imaging may be needed when X-rays are normal early on, or to tell Charcot from infection.^[1,3]

Treatment

Active stage. The foot must be protected from weight and impact so the bones can heal. This means complete non-weight-bearing protection with a cast, removable boot or brace, and crutches or a wheelchair, for a period of months. After that, custom footwear with inserts and bracing help people return to daily activities while protecting the foot.^[1] Both feet need protection, because increased load on the other foot puts it at risk too.^[1]

Long-term care. Regular checkups, daily foot inspection, blood sugar control and appropriate footwear help prevent ulcers and further collapse.^[1]

When surgery is considered

Surgery is considered when the deformity has become severe enough to be unstable, when it can’t be braced, or when it causes ulcers or infection that won’t heal.^[1] Reconstruction generally involves removing infected or damaged bone if needed, correcting the deformity, and fusing the unstable joints with screws, plates, a rod or an external frame.^[5,4]

A systematic review of 1,116 reconstructed feet found a bone fusion rate of about 86%, a rate of complications related to the technique of about 36%, a post-reconstruction amputation rate of about 5.5%, and a return to walking in about 91% of people. No fixation method was clearly better, and because the studies were not controlled and the patients were carefully selected, the evidence is of low quality.^[4] Another review suggests that the choice of fixation depends on the site of the deformity and whether there is an ulcer or infection.^[5]

Surgery in a person with Charcot foot carries a high risk of infection and other complications, and the risk is higher in people with neuropathy and diabetes.^[6] Careful preparation and close follow-up are essential. See preparing for foot and ankle surgery.

When to seek care

If you have neuropathy or diabetes and a foot becomes warm, red or swollen — even without pain — have it evaluated within a day. Early protection can prevent the bones from collapsing.