Charcot Neuroarthropathy
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Direct answer
Charcot neuroarthropathy is a progressive, destructive arthropathy of insensate joints, most often in the diabetic foot, in which minor trauma produces joint collapse. Its early stage mimics infection, with heat, swelling and bone fragmentation, and the midfoot may collapse into a rocker-bottom deformity if it goes unrecognised. Early total contact casting with strict offloading is the core treatment, and surgery is reserved for unstable or ulcerated deformity.
What you must remember
- Cause: loss of protective sensation lets repeated, unnoticed microtrauma accumulate, while increased blood flow to bone hastens resorption and fragmentation.
- Commonest causes: diabetes leads in current practice, with tabes dorsalis, leprosy, syringomyelia and alcoholic neuropathy as the other important causes.
- Typical sites: the tarsometatarsal and midfoot joints, including the Lisfranc region, and the ankle, with the knee and hip affected far less often.
- Eichenholtz stages: development with fragmentation and a hot swollen foot, coalescence of fragments, then reconstruction with remodelling and consolidation.
- Radiology: fragmentation, subluxation and dislocation, periarticular osteolysis, and later a rocker-bottom deformity, with MRI detecting marrow oedema before radiographs change.
- Key differential: osteomyelitis and gout produce similar heat and swelling, so infection is excluded before the Charcot label is given.
- Core treatment: total contact casting with strict non-weight-bearing offloading, then custom footwear and bracing, with ulcers and unstable deformity referred for surgery.
From a hot midfoot to a cast
A 58-year-old man with type 2 diabetes and reduced foot sensation notices a warm, swollen midfoot after a twisting step. X-ray shows fragments and early collapse, and his skin is intact.
- Recognise the hot foot. Warmth, swelling and redness in an insensate diabetic foot after little trauma must be treated as Charcot until proven otherwise.
- Exclude infection. Inflammatory markers, probe-to-bone testing and imaging rule out osteomyelitis, since the two can coexist and need different treatment.
- Image the foot. Plain films show fragmentation and subluxation, and MRI detects early marrow oedema when radiographs still look normal.
- Stage the disease. Eichenholtz stage 1, with fragmentation, is managed differently from the consolidated stage 3, so the stage sets the plan.
- Offload with a total contact cast. Non-weight-bearing in a total contact cast continues until the skin temperature difference between the feet falls below about 2 degrees Celsius, after which custom footwear follows.
- Plan the late deformity. Unstable, rocker-bottom or ulcerated feet are considered for reconstruction such as arthrodesis, once infection is controlled and the foot has settled.
Charcot questions in the foot clinic
Most traps arise because the hot, swollen foot looks infected.
- Trap: treating the hot, swollen diabetic foot with antibiotics alone and no offloading Correct: Charcot is a mechanical disease, so immobilisation is the core treatment and antibiotics are added only when infection is found.
- Trap: picking osteomyelitis as the answer because the foot is warm Correct: warmth and swelling are shared by both conditions, so probe-to-bone testing and markers decide, and the two can coexist.
- Trap: assuming a consolidated Charcot foot needs no further follow-up Correct: the rocker-bottom deformity and ulcers develop later, so long-term footwear and surveillance are needed.
Frequently asked questions
What is the earliest sign of Charcot neuroarthropathy?
Warmth, swelling and erythema of an insensate foot, often with a temperature difference between the two feet, are the earliest clinical signs of Charcot neuroarthropathy. Radiographs may be normal at this stage, so MRI can show marrow oedema earlier.
Which Eichenholtz stage needs total contact casting?
Total contact casting is used mainly in the active development and fragmentation stage, when the foot is hot and the bones are still unstable. Its purpose is to stop further collapse, and it is continued until the temperature difference settles.
Why is the midfoot commonly affected in Charcot neuroarthropathy?
The tarsometatarsal and midfoot joints bear repeated load during walking in an insensate foot, so unnoticed microtrauma accumulates there. The Lisfranc region is a common site, and collapse there leads to the rocker-bottom deformity.
Which conditions besides diabetes cause Charcot joints?
Tabes dorsalis from syphilis, leprosy, syringomyelia and alcoholic neuropathy are the other important causes of Charcot joints. Any condition that abolishes deep pain and protective sensation can produce the arthropathy.
How is Charcot neuroarthropathy differentiated from osteomyelitis?
Both produce heat, swelling and bone changes, so the diagnosis depends on probe-to-bone testing, inflammatory markers, MRI and sometimes bone biopsy. Charcot neuroarthropathy may coexist with infection, which needs separate treatment.