Novel ankle orthosis with elastomer-embedded flexible joint.

Area of Science:

• Biomechanics
• Biomedical Engineering
• Orthotics

Background:

• The tibialis anterior muscle (TA) plays a crucial role in foot dorsiflexion and preventing foot drop.
• Existing ankle orthoses can impose significant burdens on the TA, potentially leading to fatigue or discomfort.
• Improving toe clearance during the swing phase is essential for preventing trips and falls.

Purpose of the Study:

• To develop and evaluate a novel ankle orthosis with elastomer-embedded flexible joints (EEFJ).
• To assess the orthosis's ability to reduce the workload on the tibialis anterior muscle (TA).
• To determine if the orthosis enhances toe clearance during gait.

Main Methods:

• Fabrication of the EEFJ ankle orthosis using C-shaped springs and 3D-printed elastomer.
• In vitro strength testing to quantify supporting torque in different directions.
• Gait analysis in seven healthy young subjects to measure TA muscle activation and joint kinematics.

Main Results:

• The EEFJ orthosis demonstrated a supporting torque of 0.7-2.3 Nm for plantarflexion, with minimal torque in other directions.
• Gait experiments showed a significant reduction in TA muscle activation during initial contact and the swing phase.
• The orthosis also reduced the range of motion at initial contact.

Conclusions:

• The proposed EEFJ ankle orthosis is effective in reducing tibialis anterior muscle (TA) burden.
• The design successfully achieves improved toe clearance, potentially reducing fall risk.
• This innovative orthosis shows promise for individuals with dorsiflexion weakness or those seeking reduced muscle fatigue.