Can wounds on the metatarsal foot be classified as pressure injuries?

Wounds on the Metatarsal Foot as Pressure Injuries

Wounds on the metatarsal area of the foot can be classified as pressure injuries, particularly in patients with diabetes or peripheral neuropathy who experience loss of protective sensation.

Mechanism of Metatarsal Pressure Injuries

Metatarsal wounds develop primarily due to:

• Biomechanical factors: Excessive or persistent pressure combined with loss of protective sensation leads to tissue breakdown 1
• Force types: Shear, compressive, frictional, and tensile forces are the main causes of plantar foot ulcers 1
• Risk factors: Peripheral neuropathy, foot deformities, and previous ulceration history significantly increase risk 1

Pathophysiology

The development of metatarsal pressure injuries follows a clear pathway:

1. Initial insult: Repetitive biomechanical stress causes tissue damage
2. Callus formation: Hyperkeratosis develops at pressure points as a protective response
3. Tissue breakdown: Continued pressure leads to ulceration beneath callus
4. Wound progression: Without intervention, wounds deepen and may become infected

Peripheral neuropathy is a critical factor as it eliminates the protective pain sensation that would normally prompt behavior change to relieve pressure 1.

Diagnosis and Assessment

To properly identify metatarsal pressure injuries:

• Physical examination: Look for callus formation, ulceration, or pre-ulcerative signs at metatarsal heads
• Sensory testing: Use 10-g monofilament to assess protective sensation at plantar surface 1
• Vascular assessment: Evaluate arterial supply through pulse palpation, ABI, or toe pressures 1
• Wound probing: Use sterile blunt metal probe to assess depth and detect potential bone involvement 1

Management Approach

1. Pressure Offloading (Primary Intervention)

• For active ulcers: Use non-removable knee-high offloading devices (total contact casts or walkers) as first-line therapy 1
• For healed ulcers: Prescribe customized footwear that accommodates foot shape and reduces plantar pressure 1
• For pre-ulcerative signs: Remove abundant callus and protect with appropriate footwear modifications 1

2. Wound Care

• Debridement: Remove hyperkeratosis (callus) and necrotic tissue to properly assess wound depth 1
• Infection control: Promptly manage foot infections with appropriate antibiotics and surgical intervention if needed 1
• Dressing selection: Choose appropriate dressings based on wound characteristics and exudate level 2

3. Addressing Contributing Factors

• Vascular assessment: Evaluate for peripheral artery disease and consider revascularization if indicated 1
• Glycemic control: Optimize diabetes management to improve healing potential 1
• Footwear modification: Ensure proper fit with adequate toe box height and width 1

Prevention of Recurrence

For patients with healed metatarsal pressure injuries:

• Custom footwear: Prescribe shoes that accommodate foot deformities with pressure-redistributing insoles 1
• Regular follow-up: Monitor for pre-ulcerative signs (callus formation, redness) 1
• Patient education: Teach proper foot inspection and care techniques 1

Clinical Pitfalls to Avoid

1. Inadequate offloading: Failure to properly offload pressure is the most common reason for non-healing
2. Overlooking infection: Deep infections can be present without obvious surface signs in neuropathic patients
3. Focusing only on wound care: Without addressing the underlying pressure, wounds will recur
4. Neglecting vascular status: Adequate perfusion is essential for healing
5. Poor footwear selection: Ill-fitting shoes are a common cause of ulceration, even in patients with ischemic ulcers 1

By understanding metatarsal wounds as pressure injuries and implementing appropriate offloading strategies, healthcare providers can significantly reduce morbidity, mortality, and improve quality of life for affected patients.