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Charcot Foot
Aka: Charcot Foot, Charcot Ankle
- See also
- Charcot Joint
- Epidemiology
- Bilateral in 9 to 35%
- Age typically over 40 years old
- Most common in Diabetes Mellitus with Peripheral Neuropathy
- Type I Diabetes patients are younger but with longer standing diabetes at diagnosis of Charcot Foot
- Pathophysiology
- Progressive deterioration of weight bearing joint as a complication of Peripheral Neuropathy
- Sites of Neuroarthropathy
- Medial tarsometatarsal joint (most common site)
- Midfoot involvement accounts for 70% of cases
- Theories of pathogenesis in Diabetes Mellitus
- Neurotraumatic injury
- Repetitive minor Trauma to foot
- Loss of proprioception and Pain Sensation
- Neurovascular injury
- Repetitive minor Trauma to foot
- Autonomic vascular reflex
- Hyperemia
- Periarticular Osteopenia
- Risk Factors
- Diabetic Neuropathy (Diabetes Mellitus)
- Lifetime Prevalence of Neuroarthropathy in Diabetes Mellitus: 0.8 to 7.5%
- Lifetime Prevalence of Neuroarthropathy in Diabetes Mellitus with Neuropathy: 29-35%
- Associated with poor Diabetes control (Hemoglobin A1C >9) >15 years
- Alcoholic Neuropathy
- Sensory loss
- Cerebral Palsy
- Leprosy
- Congenital insensitivity to pain
- Other contributing factors
- Obesity
- Chemotherapy
- Trauma
- Iron Deficiency Anemia
- Rheumatoid Arthritis
- Other markers of significant Diabetic Neuropathy
- Foot Ulceration
- Retinopathy
- Nephropathy, Renal Failure or renal Transplantation
- Types
- Atrophic Neuroarthropathy
- Localized to forefoot
- Osteolysis of Metatarsal heads
- Hypertrophic Neuroarthropathy
- Affects midfoot, rearfoot and ankle)
- Eichenholtz Classification
- Stage 0: Clinical (acute inflammatory)
- Erythema, edema, and warm foot
- No fever or skin break, normal XRay, normal CBC
- Often associated with minor Trauma History
- Early diagnosis critical to prevent progression
- Stage 1 Fragmentation (Acute Charcot)
- Periarticular Fractures and joint dislocations
- Unstable and deformed foot
- Stage 2 Coalescence (Subacute Charcot)
- Bone debris resorbed
- Stage 3 Reparative (Chronic Charcot)
- Fragments fuse, resulting in re-stabilization
- Stable, but deformed foot
- Findings: Presentation
- Peripheral Neuropathy (esp Diabetes Mellitus) and Obesity in age over 40 years old AND
- Unilateral swollen limb
- Minimal pain
- Painless in up to half of patients
- Low mechanism injury (e.g. minor overuse or sprain)
- No known preceding Trauma in up to half of patients
- Signs
- Warm, swollen, erythematous lower extremity (esp. over affected joints)
- Erythema improves with elevation above heart level for 5-10 min (distinguish from infection)
- Normal features that distinguish from other diagnoses
- No fever
- No open wound
- Normal pulses
- Diagnosis
- Identify Peripheral Neuropathy
- See Peripheral Neuropathy Testing
- Loss of Achilles Reflex
- Semmes-Weinstein 10-g Monofilament
- Differentiate Osteomyelitis
- See Suspected Osteomyelitis in Diabetes Mellitus
- Probe To Bone Test (Described in Osteomyelitis)
- Brodsky Test
- Differentiates Charcot Stage 0 from Cellulitis
- Technique
- Patient supine with involved leg raised 10 minutes
- Interpretation
- Charcot Process: Swelling and erythema dissipate
- Infection: Swelling and erythema persist
- Differential Diagnosis
- Infectious conditions
- Cellulitis or Erysipelas
- Osteomyelitis
- Septic Arthritis
- Rheumatologic Conditions
- Gout
- Pseudogout
- Rheumatoid Arthritis
- Acute monoarthropathy
- Musculoskeletal conditions
- Plantar Fasciitis
- Ankle Sprain
- Foot Fracture
- Tumor
- Vascular conditions
- Deep Vein Thrombosis
- Venous Insufficiency
- Labs
- Consider labs obtained in Osteomyelitis
- Normal labs that distinguish from other diagnoses
- Normal Complete Blood Count
- Normal acute phase reactants (C-RP, ESR)
- Imaging: Foot XRay
- Precautions
- Bony destruction may not be visible on xray for 6-12 months
- Comparison bilateral weight bearing XRays
- Evaluate for instability
- May appear as ligamentous avulsion Fractures (small avulsed bone fragments)
- Evaluate for Osteomyelitis
- Atrophic Neuroarthropathy (esp. midfoot)
- Metatarsal heads have pencil point appearance
- Midfoot Fractures are often missed
- Consider additional testing for Osteomyelitis
- See Suspected Osteomyelitis in Diabetes Mellitus
- Imaging: Foot MRI
- CT Foot is an alternative, if MRI is contraindicated
- MRI or CT are preferred over bone scan
- Findings suggestive of Charcot Joint
- Periarticular Bone Marrow edema
- Progresses to cortical Fractures (and secondary deformity) if weight bearing continues
- Soft tissue edema
- Joint effusions
- Stress Fractures
- Imaging: Normal studies that distinguish from other diagnoses
- Venous Duplex Ultrasound
- Precautions
- Charcot Foot is often misdiagnosed as an alternative condition with delayed diagnosis on average, 7 months
- Consider in patients with recurrent "Cellulitis" (often improves transiently with bed rest)
- Delayed diagnosis is a risk for rigid foot deformities with significant amputation risk (RR 15-40)
- Involve specialty care early in course
- Management: General
- Step 1 Immobilization
- Total Contact Cast (TCC) or
- Prefabricated pneumatic walking brace (PPWB)
- Immobilize for 4 months until stable
- Erythema and edema resolved
- Affect limb with same Temperature as other limb
- Stabilization by XRay (repeat every 4-6 weeks)
- Step 2: Immobilize 6 to 24 months until foot stable
- Charcot Restraint Orthotic Walker (CROW)
- Indicated for anterior edema
- Ankle foot Orthosis
- Patellar tendon-bearing brace
- Step 3: Supportive Footwear
- Extra-deep shoes with custom insoles
- Additional treatment options
- Exostosectomy
- Stable chronic Charcot Foot with exostosis or ulcer
- TENS
- Low intensity Ultrasound
- Intranasal Calcitonin 200 IU (experimental)
- Bem (2006) Diabetes Care 29(6): 1392-4 [PubMed]
- Other measures that are ineffective
- Bisphosphonates
- Richard (2012) Diabetologia 55(5): 1258-64 +PMID:22361982 [PubMed]
- Management: Total Contact Cast
- Contraindications
- Wagner Grade 3 Foot Ulcer (abscess or Osteomyelitis)
- Technique
- Tubular stockinette
- One quarter inch felt
- Three layer inner plastic shell
- Fiberglass outer shell
- Protocol
- Crutch walking only
- Initially change cast after first week (due to edema)
- Later change cast every 2-4 weeks
- Management: Prefabricated pneumatic walking brace (PPWB)
- Indications
- Alternative to Total Contact Cast (above)
- Neuropathic plantar ulcer
- Contraindications
- Severe foot deformity
- Noncompliance
- Complications
- Rigid foot deformity
- Foot Ulcer or plantar ulcer
- Infection
- Amputation
- References
- Caputo (1997) Am Fam Physician 55(2):605-11 [PubMed]
- Marmolejo (2018) Am Fam Physician 97(9): 594-9 [PubMed]
- Myerson (1992) J Bone Joint Surg 74:261-9 [PubMed]
- Sommer (2001) Am Fam Physician 64(9):1591-8 [PubMed]
- Schon (1998) Clin Orthop 349:116-31 [PubMed]