II. Epidemiology

  1. Diabetic Foot Ulcers precede amputation in 85% of cases
    1. Diabetic ulcers are the most common cause of leg amputation
  2. Diabetic Foot Ulcer is associated with a 40% five year mortality
    1. Heyer (2016) Wound Repair Regen 24(2): 434-42 [PubMed]

III. Pathophysiology

  1. Sensory protection is lost (Diabetic Neuropathy)
    1. Results in chronic Trauma
    2. Tissue breaks down in Traumatized area
    3. Charcot changes result in additional pressure points
  2. Complicating factors (related to poor healing)
    1. Peripheral Vascular Disease
    2. Edema (Venous Stasis, Congestive Heart Failure)
    3. Osteomyelitis

IV. Signs

  1. Distribution: Plantar aspect of foot
    1. Toes
    2. Metatarsal heads
  2. Characteristics
    1. Crater-like appearance surrounded by a thick ring of callus
    2. Wound bed may be covered in eschar or necrotic material
    3. Deeper structures (tendons, bone) may be exposed

V. Evaluation: General

  1. Evaluate for systemic illness
    1. See Infected Diabetic Foot Ulcer
    2. Cellulitis with SIRS criteria (Sepsis)
    3. Acute Osteomyelitis (typically in children with hematogenous spread) with toxic or ill appearance
      1. Contrast with Chronic Osteomyelitis (typically in adults with local spread) which is slow, indolent
  2. Evaluate for complicating factors
    1. Osteomyelitis
      1. See Suspected Osteomyelitis in Diabetes Mellitus
      2. Erythrocyte Sedimentation Rate (ESR) >60
      3. Affected limb x-ray (or Bone Scan, MRI)
      4. Probe-to-Bone Test
    2. Retained Foreign Body
      1. Consider XRay
      2. Consider bedside soft-tissue Ultrasound
    3. Peripheral Vascular Disease
      1. Distal Pulses
      2. Lower extremity arterial Doppler Ultrasound
      3. Ankle-Brachial Index
        1. Often calcified and non-compressible in Diabetes Mellitus
        2. Results in a high ABI (>1.2) despite severe Peripheral Arterial Disease
        3. Consider Toe-Brachial Index instead
    4. Neuropathy
      1. Diabetic Neuropathy Testing (Semmes-Weinstein 10-g, 5.07-Gauge Monofilament)

VI. Evaluation: Inpatient Criteria for Foot Wound with Limb-Threatening Infection

  1. Extensive Cellulitis (>2 cm)
  2. Ascending lymphangitis
  3. Deep abcesses
  4. Osteomyelits
  5. Gangrene
  6. Critical Limb Ischemia
  7. Probe extends to bone (Probe To Bone Test)
  8. Frykberg (2006) J Foot Ankle Surg 45(5 Suppl):S1-66 [PubMed]

VII. Management: Outpatient

  1. General Measures
    1. Optimize Diabetes Mellitus Glucose Management
    2. See TIME Principle of Chronic Wound Care
    3. Graduated Walking Program
  2. Offloading is key
    1. Ongoing Trauma persists until non-weight bearing
    2. Options
      1. Use Crutches, walker or Wheelchair
      2. Darko Shoe (half shoe offloads distal foot)
      3. CAM Walker or Aircast pneumatic walker
      4. Total Contact Cast (Plaster, Fiberglass or Roll-On, preferred)
  3. Debridement
    1. Debride thick callus from wound edges (causes pressure areas)
  4. Dressings (moist Wound Healing is critical)
    1. Dry to minimal exudates
      1. Wet-to-Moist Dressing (cost effective, first line) or other Saline Gauze Dressing
      2. Hydrogel Dressing (e.g. Curasol)
    2. Moderate to heavy exudates
      1. Hydrofiber dressing (e.g. Aquacel)
    3. Other preparations with specific indications
      1. Silver products (e.g. Acticoat) may be considered for infected wounds
      2. Debridement salves (e.g. accuzyme) may be considered for Enzymatic Debridement
    4. Other more complex and expensive options
      1. Promogran
      2. Becaplermin (Regranex)
      3. Bioengineered skin graft
  5. Additional measures to consider
    1. Determine if antibiotics are appropriate
      1. See Infected Diabetic Foot Ulcer
    2. Hyperbaric oxygen
      1. Bishop (2014) Int Wound J 11(1): 28-34 [PubMed]
      2. Sharma (2021) Sci Rep 11(1):2189 [PubMed]
    3. Maggot Debridement
      1. Sun (2014) Int J Infect Dis 35:32-7 [PubMed]
  6. Measures to avoid
    1. Chronic Wounds without superinfection do not require culture

VIII. Prevention

IX. References

  1. Delaney and Khoury in Herbert (2017) EM:Rap 17(12): 2-3
  2. (2014) Presc Lett 21(12): 71
  3. Bowers (2020) Am Fam Physician 101(3):159-66 [PubMed]

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