1. Overview & Epidemiology
Lower extremity complications are a major source of morbidity and mortality.
- Amputation Risk: Adults with diabetes in Canada are 20 times more likely to undergo a non-traumatic lower limb amputation than those without diabetes.
- Hospitalization: Foot ulcers are a leading cause of hospitalization for people with diabetes.
- Recurrence: Individuals with a history of foot ulcers have a high rate of recurrence, making ongoing surveillance critical.
2. Risk Assessment
Every person with diabetes requires regular foot risk assessment.
- Frequency: Perform a foot exam at least annually, and more frequently for high-risk individuals.
- Key Risk Factors for Ulceration:
Peripheral Neuropathy (Loss of Protective Sensation).
Peripheral Arterial Disease (PAD).
Structural deformity (e.g., Charcot foot, hammer toes).
Previous ulcer or amputation.
Elevated A1C and Onychomycosis (fungal nail infection).
3. The Physical Exam (The "3-Minute Exam")
A proper foot exam includes three main components:
A. Neurological Assessment (Protective Sensation)
Tool: 10g Semmes-Weinstein Monofilament.
Method: Test specific sites on the plantar surface. Loss of sensation to the 10g monofilament is a significant independent predictor of future ulceration and amputation.
B. Vascular Assessment (Circulation)
Inspection: Look for skin color, hair growth, and temperature.
Palpation: Check dorsalis pedis and posterior tibial pulses.
Advanced Testing: Ankle-Brachial Index (ABI) is standard but may be falsely elevated (unreliable) in diabetes due to calcified arteries (medial arterial calcification). Toe Pressures (systolic toe pressure) are often more accurate in this population.
C. Dermatological/Musculoskeletal
Skin: Assess for calluses (pre-ulcerative lesion), fissures, blisters, or tinea pedis.
Structure: Look for deformities like Charcot arthropathy (collapsed arch, warmth, redness) or claw toes which increase pressure points.
4. Classification of Ulcers
Using a validated system helps predict outcomes. The guidelines highlight two systems:
- Wagner Classification: Grades 0 (intact skin) to 5 (gangrene of whole foot).
- University of Texas System: Incorporates Ischemia and Infection into the grading (Stages A, B, C, D), which improves prediction of amputation risk.
5. Management of Foot Ulcers
Treatment requires an interprofessional approach focusing on VIP: Vascular status, Infection, and Pressure off-loading.
- Debridement: Regular debridement of non-viable tissue (callus/slough) is recommended to promote healing.
- Infection:
- Uninfected Ulcers: Do NOT use antibiotics (topical or systemic) for uninfected ulcers. It promotes resistance.
- Infected Ulcers: Classify as mild (localized), moderate, or severe. Treat with empiric antibiotics covering Staph. aureus and Strep, then tailor based on deep tissue culture (swabs are unreliable).
- Off-Loading (Pressure Relief):
- Gold Standard: Total Contact Cast (TCC) or non-removable walker boot is the most effective method for healing plantar neuropathic ulcers.
- Removable Cast Walkers: Effective if worn consistently (but compliance is lower).
- Dressings: No single specific dressing type is superior. The principle is to maintain a physiologically moist wound environment.
- Adjunctive Therapies: Therapies like negative pressure wound therapy (NPWT) or hyperbaric oxygen are not recommended for routine treatment of simple ulcers but may be considered for complex/non-healing wounds.
6. Charcot Neuroarthropathy
Definition: A progressive degeneration of a weight-bearing joint, characterized by bony destruction and deformity.
Acute Phase Signs: Red, hot, swollen foot (often mistaken for cellulitis).
Differentiation: If a foot is red/hot but the patient is afebrile and WBC is normal, suspect Charcot. Elevating the foot may decrease redness in Charcot (dependent rubor) but not in cellulitis.
Treatment: Immediate immobilization (Total Contact Cast) and non-weight bearing until the acute phase resolves (temperature normalizes).
7. Diabetes Canada 2018 Clinical Practice Guidelines Recommendations
Key takeaways from the “Recommendations” section (Page S226).
Screening: Perform a foot exam at least annually to identify risk factors (neuropathy, PAD, deformity) [Grade C, Level 3].
Education: High-risk individuals should receive foot care education and professionally fitted footwear [Grade D, Consensus].
Prompt Treatment: Any foot ulcer or sign of infection requires prompt treatment by an interprofessional team [Grade C, Level 3].
Wound Care:
Debride non-viable tissue [Grade A, Level 1A].
Use dressings that maintain a moist environment [Grade D, Consensus].
There is insufficient evidence to recommend specific dressing types or antimicrobial dressings for routine use [Grade C, Level 3].
Adjunctive Therapy: Therapies like topical growth factors or dermal substitutes are not for routine use but may be considered for non-healing, non-ischemic wounds after standard care fails [Grade A, Level 1].