Thumb Brace for Distal Hyperextensibility Injury Prevention in Athletics

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Presenter(s)

Madison Burchfield, Nina Dorfner, Christian Sarro

Abstract or Description

Distal hyperextensibility, commonly known as Hitchhiker’s Thumb, is classified as a joint hypermobility disorder where the thumb is able to bend backwards past the normal point of motion. The upper interphalangeal joint is a uniaxial hinge joint acting as the origin of thumb hyperextension. Distal hyperextensibility accounts for varying degrees of extension in the upper interphalangeal joint ranging from 0° to severe 90°. The increased mobility from this trait increases the chance of injury to the thumb, which is a large problem facing athletes. 

In order to increase stability of the thumb in athletes with distal hyperextensibility, we designed a thumb brace that allows the thumb to function while preventing hyperextension. Existing orthopedic solutions restrict movement of the thumb joints and are typically used as acute injury treatment instead of prevention. User needs such as preserving grip strength, cost-effectiveness, comfortability, washability, and joint mobility are all considered in our design. The brace protects both the interphalangeal (IP) and the lower metacarpophalangeal (MCP) joint. 

A minimum viable prototype was constructed out of recycled finger splints, Velcro straps, and hot glue. After evaluating challenges with the first prototype, the design was modified and modeled on Fusion360. The next prototype version will be 3D printed and undergo force tests as outlined in the device verification and validation plan. The final design will be made out of polypropylene, Velcro, and dry fast foam to provide athletes with hitchhiker’s thumb the stability they require for injury prevention during physical activity.