Design and Fabrication of an Elbow Motion Simulator

by Magnusen, Joshua

Uncertainty and a lack of knowledge regarding restoration of proper function following an elbow injury create a need for expanding the understanding of elbow operation. An elbow motion simulator that is capable of producing motion in a cadaver forearm is designed and developed. This device will advance the capabilities of similar preceding elbow simulators by physically simulating the full range of motion and force-loading conditions in the elbow. Electric cylinders are used to simulate the muscles. The five muscles that are modeled are the biceps, brachialis, triceps, brachioradialis, and pronator teres. A braided cable attached to the cylinders inserts on the arm at each muscles tendonous insertion. Custom-designed pulley systems are developed for the muscles to maintain an accurate line of action within the cable by preserving a physiological moment arm about the joint of rotation. The arm specimen is secured by means of a humeral clamp that holds the humeral shaft secure during experimentation. The device can be rotated to test in either a varus or a valgus orientation. Preliminary testing with a wooden arm model is performed to verify the simulators capabilities.