What are the key considerations in managing diabetic foot ulcers?

Diabetic Foot Ulcers: Key Characteristics and Management

In diabetic foot ulcers, neuropathy affects both somatic and autonomic nerves, the forefoot (not heel) is the most common location, motor neuropathy primarily affects toe extensors (not flexors), and the ankle-brachial index is not an accurate measure of ischemia in diabetes due to arterial calcification. 1

Neuropathy in Diabetic Foot Ulcers

• Diabetic neuropathy affects both somatic and autonomic nerves, not just somatic nerves 1
• Autonomic neuropathy leads to decreased sweating and dry skin, increasing risk of cracking and ulceration 2
• Peripheral sensory neuropathy is the single most common component cause for foot ulceration, found in 78% of people with diabetes with ulcerations 1
• The triad of peripheral sensory neuropathy, minor trauma, and foot deformity is present in >63% of patients with diabetic foot ulcers 1

Location and Characteristics of Diabetic Foot Ulcers

• The forefoot is the most common location for diabetic foot ulcers, not the heel 1
• Ill-fitting shoes are the most frequent cause of ulceration, even in patients with 'pure' ischemic ulcers 1
• Motor neuropathy primarily affects toe extensors (not flexors), leading to clawing of toes and increased pressure on metatarsal heads 2
• A warm, dry foot (not cold, dry) is the classic finding in neuropathic ulcers due to arteriovenous shunting and decreased sweating 2

Vascular Assessment in Diabetic Foot Ulcers

• The ankle-brachial index is NOT an accurate measure of the degree of ischemia in diabetic patients due to arterial calcification 1
• Ankle pressure might be falsely elevated because of calcification of the arteries in diabetic patients 1
• Preferred tests for vascular assessment include toe pressure measurements or transcutaneous pressure of oxygen (TcPO2) 1
• Initial screening for peripheral arterial disease should include assessment of lower-extremity pulses, capillary refill time, rubor on dependency, pallor on elevation, and venous filling time 1

Risk Stratification and Examination Frequency

• All people with diabetes should undergo a comprehensive foot examination at least annually 1
• The International Working Group on Diabetic Foot risk stratification system guides examination frequency 1:
  • Category 0 (Very low risk): No LOPS and no PAD - Examine annually 1
  • Category 1 (Low risk): LOPS or PAD - Examine every 6-12 months 1
  • Category 2 (Moderate risk): LOPS + PAD, or LOPS + foot deformity, or PAD + foot deformity - Examine every 3-6 months 1
  • Category 3 (High risk): LOPS or PAD and history of foot ulcer, amputation, or end-stage renal disease - Examine every 1-3 months 1

Management Approach for Diabetic Foot Ulcers

• An interprofessional approach facilitated by a podiatrist in conjunction with other appropriate team members is recommended for individuals with foot ulcers and high-risk feet 1
• Pressure relief using total contact casts, removable cast walkers, or "half shoes" is the mainstay of initial treatment 3
• Sharp debridement and management of underlying infection and ischemia are critical in the care of foot ulcers 3
• For chronic diabetic foot ulcers that have failed to heal with optimal standard care alone, consider adjunctive treatments such as negative-pressure wound therapy, placental membranes, bioengineered skin substitutes, or autologous fibrin and leukocyte platelet patches 1

Common Pitfalls to Avoid

• Failing to assess for both neuropathic and vascular components in diabetic foot ulcers 2
• Relying solely on ankle-brachial index for vascular assessment 1
• Neglecting pressure offloading as a critical component of treatment 2
• Inadequate debridement of necrotic tissue and callus 2
• Failing to provide appropriate footwear for prevention of recurrence 1