Tissue Stress Theory in Orthotic Design

Load Reduction Framework

Tissue stress theory provides a biomechanical framework for understanding how orthotics can reduce pathological tissue stress. By altering ground reaction forces and joint moments, orthotics can unload stressed tissues while maintaining functional movement patterns.

Primary Mechanisms

• Load redistribution across plantar surface
• Moment arm modification at key joints
• Tissue elongation reduction
• Shock absorption enhancement

Clinical Applications

Plantar Fasciitis

Arch support reduces plantar fascia elongation during midstance. Heel cushioning decreases impact forces. Medial posting controls excessive pronation that increases fascia stress.

Posterior Tibial Tendon Dysfunction

Medial arch support reduces PTTD workload. Medial posting decreases pronation moments. Heel cup provides additional stability for hindfoot alignment.

Metatarsalgia

Metatarsal pads redistribute forefoot pressure. Arch support improves weight distribution. Rocker sole modifications reduce forefoot loading during push-off.

Key Indications & Contraindications

Pathology	Use When	Avoid If
Tissue Overload	Chronic stress conditions, repetitive strain	Acute trauma, infection, tumor
Biomechanical Dysfunction	Compensatory movement patterns	Neuromuscular disorders, severe rigidity
Load Distribution Issues	Pressure concentration, callus formation	Severe peripheral neuropathy, open wounds

When to Escalate to In-Person Care

Consider referral when tissue stress theory applications fail to improve symptoms, structural deformities progress, or neurological symptoms develop.