A Novel Brace Design for Ulnar Collateral Ligament Injury Prevention and Rehabilitation

Abstract

Ulnar Collateral Ligament (UCL) complete tears are only known to be remedied by Tommy John Surgery, a reconstructive surgery that utilizes the palmaris longus tendon weaved in and around drilled holes in the humerus and ulna to reinforce and recreate the UCL. First completed in the mid 70s, this surgery has become more and more common for younger players in the last two decades. This study searches for a way to hinder the climbing growth of this injury, which is known to be caused by overuse of the throwing arm. A brace was designed and built to provide stabilizing forces to the elbow joint, and was tested on five former baseball players using a commercial EMG device. Due to the stabilizing forces on the brace, if the elbow flexion is less or greater than 45°, the brace will add a moment force on the elbow in the direction of the 45° flexion angle. In the beginning phases of throwing, the biceps voltages of two subjects decreased with the application of the brace, while three subjects showed the opposite effect. It was concluded that the two subjects with decreased biceps loads were allowing the brace to maintain its preferred 45° flexion, while the other three subjects worked against it. The EMG measurements showed consistently that the application of the brace decreased the voltage potentials of the muscles crossing over the elbow joint during the deceleration phase of throw.