Charcot joint

Last revised by Mostafa El-Feky on 21 Nov 2022

Charcot joint, also known as a neuropathic joint or Charcot (neuro/osteo)arthropathy, refers to a progressive degenerative/destructive joint disorder in patients with abnormal pain sensation and proprioception.

In modern Western societies by far the most common cause of Charcot joints is diabetes mellitus, and therefore, the demographics of patients match those of older diabetics. Prevalence differs depending on the severity of diabetes mellitus 10:

  • ~0.1% in general diabetic population
  • ~15% in high-risk diabetic population
  • ~30% in patients with peripheral neuropathy

Patients present insidiously or are identified incidentally, or as a result of investigation for deformities. Unlike septic arthritis, Charcot joints although swollen are normal temperature without elevated inflammatory markers. Importantly, they are painless. 

The pathogenesis of a Charcot joint is thought to be an inflammatory response from a minor injury that results in osteolysis. In the setting of peripheral neuropathy, both the initial insult and inflammatory response is not well appreciated, allowing ongoing inflammation and injury 10.

Charcot joints are typically unilateral but are bilateral in ~20% (range 5.9-39.3%) of cases 10. There are two patterns of Charcot joint: atrophic and hypertrophic.

  • most common form 1
  • occurs earlier 2
  • has an acute progression
  • characterized by reabsorption of the ends of the affected bone
  • joint destruction with resorption of fragments
  • an absence of osteosclerosis and osteophytes
  • mainly occurs in non-weight bearing joints of the upper limb 1
  • only sensory nerves affected
  • slow progression
  • joint destruction with periarticular debris/bone fragmentation
  • initially widened then narrowed joint space
  • presence of osteosclerosis and osteophytes 1
  • absence of osteoporosis (unless joint is infected) 3

Sensorimotor and autonomic neuropathies of various etiologies are the primary predisposing factor. The most common etiology varies by the involved joint 11:

Less established causes:

Some of these can be recalled with the "S" mnemonic.

Charcot arthropathy appears as a destructive and disorganizing process centered in the joint and affecting surrounding bones, which may mimic severe osteoarthritis or septic arthritis 11. Manifestations depend on stage 15:

  • development/fragmentation/dissolution: subchondral osteopenia is the earliest finding 10, followed by bony fragmentation (with formation of debris seen as intraarticular loose bodies) and joint malalignment (subluxation or dislocation due to ligamentous laxity)
  • coalescence: bony consolidation begins with subchondral sclerosis, periosteal bone formation, and fusion of the larger fragments and absorption of the smaller fragments
  • reconstruction/reconstitution: remodeling occurs with rounding of fragments and ankylosis, making deformity permanent

General characteristics may be recalled with the six Ds mnemonic.

MRI plays an important role in diagnosing complications, assessing the extent of the disease, and presence of osteomyelitis.

  • T1
    • involved joints appear diffusely swollen, showing decreased signal intensity
    • fat planes adjacent to ulcerated skin show decreased signal intensity
    • if superinfected with a gas-producing organism, there will be a loss of signal intensity. 
  • T1 C+ (Gd): inflammatory areas show enhancement, with central non-enhancing necrotic areas
  • STIR
    • early infection: increased signal intensity due to marrow edema
    • later stages: loss of demarcation of cortical outline and cortical destruction

The French pathologist and neurologist Jean-Martin Charcot (1825-1893), the "father of neurology", was the first person to give a detailed description of the neuropathic aspect of this condition in 1868 in a patient suffering syphilis 16.

Imaging differential considerations include:

Useful MRI features that support superimposed osteomyelitis on a Charcot joint include 4:

  • sinus tract
  • diffuse marrow signal abnormality
  • replacement of soft tissue fat
  • thick rim enhancement
  • joint erosion
  • ghost sign

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Cases and figures

  • Case 1: involving spine
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  • Case 3
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  • Case 4
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  • Case 5
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  • Case 6
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  •  Case 7
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  • Case 8
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  • Case 9: diabetic neuropathy
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  • Case 10
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  • Case 11: diabetic neuropathy
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  • Case 12
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  • Case 13
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  • Case 14
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  • Case 15
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  • Case 16
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  • Case 17
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  • Case 18
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  • Case 19
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  • Case 20
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  • Case 21
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  • Case 22: involving spine
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