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Charcot Foot

See also
1. Charcot Joint
Epidemiology
1. Bilateral in 9 to 35%
Pathophysiology
1. Progressive deterioration of weight bearing joint
2. Sites of Neuroarthropathy
  1. Medial tarsometatarsal joint (most common site)
  2. Midfoot involvement accounts for 70% of cases
3. Theories of pathogenesis in Diabetes Mellitus
  1. Neurotraumatic injury
    1. Repetitive minor trauma to foot
    2. Loss of proprioception and Pain Sensation
  2. Neurovascular injury
    1. Repetitive minor trauma to foot
    2. Autonomic vascular reflex
      1. Hyperemia
      2. Periarticular Osteopenia
Causes
1. Diabetic Neuropathy (Diabetes Mellitus)
  1. Prevalence of Neuroarthropathy: 0.8 to 7.5%
  2. Associated with poor Diabetes control >15 years
2. Alcoholic Neuropathy
3. Sensory loss
  1. Cerebral Palsy
  2. Leprosy
  3. Congenital insensitivity to pain
Types
1. Atrophic Neuroarthropathy
  1. Localized to forefoot
  2. Osteolysis of metatarsal heads
2. Hypertrophic Neuroarthropathy
  1. Affects midfoot, rearfoot and ankle)
  2. Eichenholtz Classification
    1. Stage 0: Clinical (acute inflammatory)
      1. Erythema, edema, and warm foot
      2. No fever or skin break, normal XRay, normal CBC
      3. Often associated with minor Trauma History
      4. Early diagnosis critical to prevent progression
    2. Stage 1 Fragmentation (Acute Charcot)
      1. Periarticular Fractures and joint dislocations
      2. Unstable and deformed foot
    3. Stage 2 Coalescence (Subacute Charcot)
      1. Bone debris resorbed
    4. Stage 3 Reparative (Chronic Charcot)
      1. Fragments fuse, resulting in re-stabilization
      2. Stable, but deformed foot
Diagnosis
1. See Peripheral Neuropathy Testing
2. See Suspected Osteomyelitis in Diabetes Mellitus
3. Probe to Bone Test (Described in Osteomyelitis)
4. Brodsky Test
  1. Differentiates Charcot Stage 0 from Cellulitis
  2. Technique
    1. Patient supine with involved leg raised 10 minutes
  3. Interpretation
    1. Charcot Process: Swelling and erythema dissipate
    2. Infection: Swelling and erythema persist
Labs
1. Consider labs obtained in Osteomyelitis
Radiology: Foot XRay
1. Comparison bilateral weight bearing XRays
  1. Evaluate for instability
  2. Evaluate for Osteomyelitis
2. Atrophic Neuroarthropathy
  1. Metatarsal heads have pencil point appearance
3. Consider additional testing for Osteomyelitis
  1. See Suspected Osteomyelitis in Diabetes Mellitus
Associated conditions
1. Plantar ulcer
Management: General
1. Step 1 Immobilization
  1. Total Contact Cast (TCC) or
  2. Prefabricated pneumatic walking brace (PPWB)
2. Immobilize for 4 months until stable
  1. Erythema and edema resolved
  2. Affect limb with same temperature as other limb
  3. Stabilization by XRay (repeat q4-6 weeks)
3. Step 2: Immobilize 6 to 24 months until foot stable
  1. Charcot Restraint Orthotic Walker (CROW)
    1. Indicated for anterior edema
  2. Ankle foot orthosis
  3. Patellar tendon-bearing brace
4. Step 3: Supportive Footwear
  1. Extra-deep shoes with custom insoles
5. Additional treatment options
  1. Exostosectomy
    1. Stable chronic Charcot foot with exostosis or ulcer
  2. TENS
  3. Low intensity ultrasound
  4. Bisphosphonate (experimental)
Management: Total Contact Cast
1. Contraindications
  1. Wagner Grade 3 Foot Ulcer (abscess or Osteomyelitis)
2. Technique
  1. Tubular stockinette
  2. One quarter inch felt
  3. Three layer inner plastic shell
  4. Fiberglass outer shell
3. Protocol
  1. Crutch walking only
  2. Initially change cast after first week (due to edema)
  3. Later change cast every 2-4 weeks
Management: Prefabricated pneumatic walking brace (PPWB)
1. Indications
  1. Alternative to Total Contact Cast (above)
  2. Neuropathic plantar ulcer
2. Contraindications
  1. Severe foot deformity
  2. Noncompliance
References

Rheumatology Book

Miscellaneous

Myofascial Pain

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Charcot Foot

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