Elbow Flexion Assist Orthosis for Arthrogryposis

Area of Science:

• Orthotics and Prosthetics
• Rehabilitation Engineering
• Biomedical Device Design

Background:

• Arthrogryposis multiplex congenita (AMC) frequently causes biceps muscle weakness, impairing elbow flexion and hand-to-mouth activities.
• Existing assistive devices may lack the specific torque control needed for dynamic functional movements.

Purpose of the Study:

• To design and prototype a novel elbow-flexion assist orthosis for individuals with AMC.
• To evaluate the device's ability to provide assistive elbow torque and improve functional reach.

Main Methods:

• A spring-powered orthosis with a unique sliding joint mechanism was developed.
• Prototype testing involved a user with AMC, with occupational therapists measuring elbow flexion.
• Benchtop torque measurements were conducted and compared with in-user trial data.

Main Results:

• The orthosis demonstrated an increasing torque output as the elbow flexed, aiding in lifting the hand towards the mouth.
• Active elbow flexion improved from 87 degrees without the device to 120 degrees with the orthosis.
• The device allowed for controlled elbow extension to a position of no applied torque.

Conclusions:

• The developed prototype is a lightweight, spring-driven elbow-flexion orthosis.
• The device is relatively easy to fabricate and can be worn discreetly under clothing.
• It effectively provides assistive torque against gravity, enhancing elbow flexion for users with AMC.