Charcot arthropathy, also known as Charcot neuroarthropathy or Charcot foot and ankle, is a syndrome in patients who have peripheral neuropathy, or loss of sensation, in the foot and ankle. Patients may experience fractures and dislocations of bones and joints with minimal or no known trauma.
Initially, there may be swelling, redness and increased warmth of the foot and ankle. Later, when fractures and dislocations occur, there may be severe deformities of the foot and ankle, including collapse of the midfoot arch (often called rocker bottom foot) or instability of the ankle and hindfoot. The syndrome progresses through three general stages:
Charcot foot occurs in patients with peripheral neuropathy resulting from diverse conditions including diabetes mellitus, leprosy, syphilis, poliomyelitis, chronic alcoholism, or syringomyelia. Repetitive microtrauma that exceeds the rate of healing may cause fractures and dislocations. Changes in circulation may cause resorption of bone, weakening the bone and increasing susceptibility to fracture and dislocation.
Charcot arthropathy may affect any part of the foot and ankle. Multiple regions may be involved. Fractures and dislocations frequently involve several bones and joints, with extensive fragmentation and deformity.
The time between the start of symptoms and a diagnosis may be several weeks or months. Often Charcot arthropathy is misdiagnosed initially because symptoms can mimic those of an injury or infection. Diagnosis is based on a high likelihood for this problem in patients with neuropathy. Increased redness, swelling, and warmth may be the only early signs. Immobilization and elevation can help to differentiate between infection and early Charcot. Some patients have pain. Early images may show soft tissue swelling with no bony changes, but repeat X-rays several weeks or months later may show bone and joint changes.
Healing may take several months. Healing times after surgery may be twice the usual duration than for a non-diabetic foot. With Charcot foot and ankle, healing after fusion may require six months of protection and orthoses.
Charcot foot and ankle may recur or flare up. Also, it is common for both feet to be affected, which can make impairment permanent. Patients use protective footwear and orthoses, and limit standing and walking to that required for activities of daily living. Regular lifelong follow-up is required with a specialist.
Severe deformities may include collapse of the midfoot arch (called rocker bottom foot) with associated plantar midfoot ulcer. Deformities may occur in any part of the foot and ankle and result in ulcers from bony pressure against the shoe or ground; ulcers may become infected, and infections may be limb- and life-threatening. Some Charcot joints, such as the ankle, may heal with fibrous tissue (non-union) and this may result in gross instability (“floppy foot”) that may predispose to ulcers and may be difficult to support with braces.