Gait plates are an extension to the front edge of a foot orthotic to try and induce a change in the angle of gait. A medial extension is supposed to induce a reduction in the gait angle and a lateral extension is supposed to induce an increase in the gait angle.
http://www.podiatry-arena.com/podiatry-forum/tags/index.php?tag=/gait-plates/ (Podiatry Arena)
http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=2889 (Podiatry Arena)
http://www.podiatry-arena.com/podiatry-forum/showthread.php?t=82404 (Podiatry Arena)
http://www.podiatryabc.com/g-is-for-gait-plates/ (Podiatry ABC)