7.2 Diabetic Foot Self-Inspection & Footwear Education

Diabetic Foot Self-Inspection & Footwear Education

Diabetic foot ulceration (DFU) is one of the most severe complications of diabetes mellitus, serving as the leading antecedent to non-traumatic lower extremity amputation. Over 85% of diabetic limb amputations are preceded by a foot ulcer. The triad of diabetic peripheral neuropathy, minor mechanical trauma, and peripheral vascular compromise creates an environment where tissue breakdown occurs silently. Educating patients and caregivers in daily foot self-inspection, foot hygiene, and appropriate footwear adherence is the single most effective intervention for preventing primary and recurrent foot ulcers.

---

Pathophysiology of LOPS & Silent Tissue Injury

Diabetic peripheral neuropathy affects sensory, motor, and autonomic nerve fibers:

• Sensory Neuropathy: Leads to Loss of Protective Sensation (LOPS), defined clinically as the inability to perceive the 10-gram (5.07 Semmes-Weinstein) monofilament at critical plantar testing sites. Without LOPS, patients cannot feel pain from high plantar pressure, tight shoes, embedded pebbles, blisters, or thermal burns.
• Motor Neuropathy: Causes atrophy of intrinsic foot muscles, leading to muscle imbalance, fallen arches, high insteps, and digital deformities such as claw toes and hammer toes. These deformities create focal bony prominences subjected to extreme peak plantar pressures.
• Autonomic Neuropathy: Reduces or eliminates sweat production (anhidrotic skin), resulting in dry, hyperkeratotic, cracked skin that easily forms painful fissures and portals for bacterial entry.

---

Systematic Daily Foot Inspection Protocol

Every patient with diabetes—especially those diagnosed with LOPS—must be taught a structured daily foot inspection routine integrated into their daily habit structure (e.g., every morning upon dressing or every evening before bed).

Step-by-Step Inspection Technique

1. Lighting & Setup: Conduct inspection in a brightly lit room. Patients with limited spinal flexibility, obesity, or hip arthritis must use a non-breakable handheld telescoping mirror or place a mirror on the floor to view the bottom of their feet.
2. Plantar Surface & Heel: Inspect the entire sole of the foot, paying specific attention to high-pressure areas: the first, third, and fifth metatarsal heads, the plantar hallux, and the heel calcaneus.
3. Interdigital Spaces: Gently separate all five toes to inspect the web spaces for maceration (white, soggy skin), fungal infection (tinea pedis), interdigital calluses, or hidden cracking.
4. Dorsum & Borders: Examine the tops of the toes, nail margins, and medial/lateral borders for redness, swelling, blisters, or friction calluses.
5. Skin Temperature Assessment: Instruct patients or caregivers to feel both feet with the palm or dorsum of their hand. A localized area of warmth compared to the opposite foot—specifically a temperature differential ΔT > 2.2°C (> 4.0°F)—indicates acute pre-ulcerative deep tissue inflammation, Charcot neuroarthropathy, or early infection requiring prompt clinical evaluation.

---

Footwear Guidelines & Daily Inspection Habits

Improper or ill-fitting footwear is responsible for up to 50% of new diabetic foot ulcers. Patients with LOPS must adopt strict footwear management principles.

Absolute Prohibition of Barefoot Walking

Walking barefoot—or walking in thin socks, slippers, or open-toed sandals—must be strictly prohibited at all times, both outdoors and indoors on carpeted or tiled floors. A single step onto a small pin, toy, carpet staple, or hard floor corner can puncture insensate tissue and trigger osteomyelitis.

Professional Shoe Fitting Criteria

1. Timing of Fitting: Shoes must always be fitted in the late afternoon, when foot volume is greatest due to physiological dependent edema.
2. Toe Box Clearance: Ensure a clearance of 3/8 to 1/2 inch (1.0 to 1.3 cm) between the end of the longest toe and the inside front of the shoe when standing.
3. Structural Requirements: Shoes must feature a broad, high toe box (preventing digital compression), a cushioned removable footbed to accommodate custom orthotic insoles, a rigid shank, a firm heel counter, and adjustable closures (Velcro straps or laces). Stiff rocker-bottom soles are recommended to reduce forefoot peak pressures.

Pre-Donning Footwear Check

Sensory-deficient patients must form the mandatory habit of manually inspecting the inside of both shoes before inserting their feet:

• Invert the shoe and shake out foreign objects (pebbles, coins, small toys).
• Run a hand smoothly inside the entire shoe interior to feel for torn linings, bunched insoles, exposed stitching, or sharp protruding tacks.

---

Hosiery & Toenail Care Protocols

Sock Selection Criteria

• Material: Recommend seamless, non-binding, moisture-wicking synthetic fiber blends (e.g., acrylic, polyester, CoolMax) that draw perspiration away from the skin. 100% cotton socks should be avoided because cotton retains moisture, causing skin maceration and friction.
• Color: Socks should be light-colored (white or light gray) so that drainage, pus, or blood from unperceived injuries is immediately visible on the fabric upon removal.

Safe Toenail Trimming Guidelines

• Cut toenails straight across and file corners gently with an emery board. Never round the edges down into the lateral nail folds, as this precipitates ingrown toenails and paronychia.
• Patients must never use razor blades, scissors, or over-the-counter chemical corn/callus removers (which contain salicylic acid that causes chemical tissue burns).
• Patients with LOPS, peripheral arterial disease (PAD), thickened fungal nails (onychomycosis), or visual impairment must be referred to a podiatrist for routine professional nail and callus management.