Foot bone structure and plantar soft tissue deformation behavior in different functional positions

Area of Science:

• Biomechanics
• Orthopedics
• Human Anatomy

Background:

• Limited understanding of dynamic foot arch deformation during gait.
• Focus on static foot structure versus dynamic changes in bones and soft tissues.
• Need to analyze arch motion across key gait phases.

Purpose of the Study:

• Evaluate dynamic changes in foot bones and plantar soft tissues during gait.
• Analyze sagittal plane arch motion during non-weight-bearing, weight-bearing, and tiptoe positions.
• Investigate the influence of arch flexibility on gait mechanics.

Main Methods:

• Three-dimensional (3D) plantar scans and X-ray imaging of 67 participants.
• Measurements of radiographic angles (e.g., talo-first metatarsal, calcaneal pitch) and derived parameters (arch index, arch volume).
• Analysis across three key gait positions: non-weight-bearing, weight-bearing, and tiptoe.

Main Results:

• Significant differences in radiographic angles and morphological parameters across gait positions (P<0.001).
• Calcaneal pitch and medial arch angles showed notable changes; arch volume increased by 48.71% at tiptoe vs. weight-bearing.
• Flexible arches exhibited significantly greater changes in arch angles compared to stiff arches during positional transitions.

Conclusions:

• Foot arch dynamics during gait are intricate, involving mechanisms like the windlass effect for arch reconstruction.
• Arch flexibility does not alter arch reconstruction at the end of the support phase but affects weight-bearing buffering patterns.
• Findings enhance understanding of foot biomechanics, aiding in foot function assessment, orthotic design, and therapeutic strategies.