How do I perform a neurovascular examination of the feet?

Neurovascular Examination of the Feet

A comprehensive neurovascular examination of the feet should include inspection of the skin, assessment of foot deformities, neurological assessment (10-g monofilament testing with at least one other assessment: pinprick, temperature, vibration), and vascular assessment including pulses in the legs and feet. 1, 2

Components of the Neurovascular Examination

1. History Taking

Before beginning the physical examination, obtain relevant history:

• Prior history of ulceration, amputation, or Charcot foot 1
• History of angioplasty or vascular surgery 1
• Smoking history 1
• Symptoms of neuropathy (pain, burning, numbness) 1, 3
• Symptoms of vascular disease (leg fatigue, claudication, rest pain) 1, 3
• History of retinopathy and renal disease 1

2. Skin Inspection

• Examine skin integrity, looking for:
  • Ulcerations or pre-ulcerative lesions 1, 4
  • Calluses or areas of hyperemia 3
  • Dryness, scaling, or fungal infections 4
  • Color changes (rubor, pallor) 1, 2

3. Neurological Assessment

• 10-g monofilament testing (essential test):
  • Test multiple sites on plantar surface of each foot 1, 2
  • Absent sensation indicates loss of protective sensation (LOPS) 1
• Perform at least one additional neurological test:
  • Pinprick sensation test 1, 5
  • Temperature perception 1
  • Vibration testing using 128-Hz tuning fork 1, 3
  • Ankle reflex assessment 3, 6
• Interpretation: Absent monofilament sensation plus one other abnormal test confirms LOPS 1, 2

4. Vascular Assessment

• Palpate pedal pulses:
  • Dorsalis pedis artery 1
  • Posterior tibial artery 1
• Additional vascular assessment:
  • Capillary refill time 1, 2
  • Rubor on dependency 1, 2
  • Pallor on elevation 1, 2
  • Venous filling time 1, 2
• For abnormal findings, consider referral for:
  • Ankle-brachial index testing 3, 7
  • Doppler ultrasound with pulse volume recordings 2, 7
  • Toe pressure measurements (more accurate in diabetes) 2, 7

5. Musculoskeletal Assessment

• Assess for foot deformities:
  • Bunions 1, 2
  • Hammertoes 1, 2
  • Prominent metatarsal heads 1
  • Charcot foot deformity 8
• Evaluate joint range of motion 9

Risk Stratification

Based on the examination findings, patients can be stratified into risk categories:

• Very low risk: No LOPS and no PAD - Annual examination 10
• Low risk: LOPS or PAD - Examination every 6-12 months 10
• Moderate risk: LOPS + PAD, or LOPS + foot deformity, or PAD + foot deformity - Examination every 3-6 months 10
• High risk: LOPS or PAD with history of foot ulcer, amputation, or end-stage renal disease - Examination every 1-3 months 10

Common Pitfalls and Caveats

• Ankle-brachial indices may be falsely elevated in patients with diabetes due to arterial calcification; toe pressures are more reliable 2, 7
• Classic signs of infection (redness, warmth) may be blunted in patients with neuropathy or ischemia 4
• Examination should be performed with the patient both weight-bearing and non-weight-bearing 11
• Patients with visual difficulties or physical constraints may need assistance with daily foot inspection 12
• The triad of peripheral sensory neuropathy, minor trauma, and foot deformity is present in >63% of diabetic foot ulcerations - be vigilant for all three factors 2, 13

Patient Education

For patients with abnormal findings, provide education on:

• Daily foot inspection using palpation or visual inspection with an unbreakable mirror 1, 10
• Proper nail and skin care 6, 10
• Appropriate footwear selection 12, 10
• Importance of regular follow-up based on risk category 2, 10