Assessment of a Foot with Diabetic Foot Ulcer
Follow a standardized evaluation strategy that addresses ulcer type, cause, site/depth, and signs of infection—this systematic approach guides all subsequent treatment decisions. 1
Classify the Ulcer Type
Determine whether the ulcer is neuropathic, neuro-ischemic, or purely ischemic through history and clinical examination. 1
Vascular Assessment
- Palpate dorsalis pedis and posterior tibial pulses in all patients 1
- Measure ankle-brachial index (ABI) using Doppler ultrasound if equipment is available 1
- Measure toe-brachial index (TBI) when ABI is unreliable; TBI ≥0.75 excludes PAD 1
- Consider toe pressure or transcutaneous oxygen pressure (TcPO2) measurements in selected cases 1
- Toe systolic blood pressure <30 mmHg suggests PAD and inability to heal—refer immediately for vascular evaluation 1
Neurological Assessment
- Test for loss of protective sensation (LOPS) using 10-g monofilament at multiple plantar sites 1
- Perform at least one additional neurological test: pinprick, temperature perception, ankle reflexes, or vibratory perception with 128-Hz tuning fork 1
- Absent monofilament sensation plus one other abnormal test confirms LOPS 1
Identify the Cause
Examine the patient's shoes and footwear behavior meticulously—ill-fitting shoes and walking barefoot with insensitive feet are the most frequent causes of ulceration, even in purely ischemic ulcers 1
Determine Site and Depth
Location Patterns
- Neuropathic ulcers: typically occur on plantar surface or over bony deformities 1
- Ischemic and neuro-ischemic ulcers: more common on toe tips or lateral foot borders 1
Depth Assessment
- Debride neuropathic ulcers with callus and necrosis as soon as possible to enable adequate depth assessment 1
- Do NOT debride non-infected ulcers with signs of severe ischemia 1
- Use a sterile metal probe to assess if bone can be touched (probe-to-bone test)—this suggests osteomyelitis, especially in longstanding or deep wounds 1
- Neuropathic ulcers can usually be debrided without local anesthetic 1
Assess for Infection
Clinical Diagnosis
Diagnose infection by the presence of at least two signs or symptoms of inflammation: redness, warmth, induration, pain/tenderness, OR purulent secretions 1
Critical caveat: These signs may be blunted by neuropathy or ischemia, and systemic findings (fever, elevated white blood count) are often absent 1
Infection Severity Classification (IDSA/IWGDF System)
- Grade 1 (Uninfected): No symptoms or signs of infection 1, 2
- Grade 2 (Mild): Local infection involving only skin and subcutaneous tissue; erythema >0.5 to ≤2 cm around ulcer 1, 2
- Grade 3 (Moderate): Erythema >2 cm OR involvement of deeper structures (abscess, osteomyelitis, septic arthritis, fasciitis) WITHOUT systemic signs 1, 2
- Grade 4 (Severe): Local infection WITH systemic inflammatory response syndrome (SIRS): temperature >38°C or <36°C, heart rate >90 bpm, respiratory rate >20 breaths/min, or WBC >12,000 or <4,000 1, 2
Osteomyelitis Assessment
Assess for osteomyelitis in patients with: 1
- Longstanding wounds
- Deep wounds
- Wounds overlying bone
- Positive probe-to-bone test
Obtain plain radiographs for screening in most cases 1
Assess for Foot Deformities
Examine for bunions, hammertoes, Charcot joint, prominent metatarsals, and other deformities that increase plantar pressures and ulceration risk 1
Additional Risk Factors to Document
- Poor glycemic control (HbA1c) 1
- Smoking history 1
- Prior ulceration or amputation 1
- Presence of retinopathy or nephropathy 1
- Pre-ulcerative signs: calluses, blisters, ingrown/thickened nails, fungal infections 1
Consider Advanced Classification Systems
Use the WIfI classification system (Wound, Ischemia, foot Infection) when resources and vascular surgery expertise are available, particularly in cases with suspected or confirmed PAD 1, 2