Development of a Novel In-Vitro Simulator for Elbow Motion

In-vitro simulation of active joint motion is useful to compare various rehabilitation protocols and surgical procedures. However to date, simulated active elbow flexion has only been achieved in the vertical orientation, in which the gravity load direction is constant. This makes vertical flexion analogous to lifting a weight. Flexion in the varus, valgus and horizontal orientations (of the humerus) are more challenging because gravity load resistance reverses direction part way through flexion, thus requiring more refined muscle control. Furthermore, horizontal flexion generates exceptionally high muscle and joint forces, while varus and valgus flexion challenge the stability of elbow joint articulation.