Abstract: A hinge system for a knee brace features a flexion-extension regulating device which is adapted to engage an end portion of the knee brace's upper strut. An elongated main slot is formed through the regulating device to provide a fixed boundary for limiting range of motion. A motion limiting member is connected to the regulating device and is further adapted for connection to an end portion of the knee brace's lower strut. The motion limiting member includes a motion limiter that is disposed within the main slot. The motion limiter is caused to move therealong when the upper and lower struts pivot about a user's knee joint. By confining the motion limiter within the fixed boundary formed by the main slot, the hinge system ensures that the user's knee joint flexes and extends within the prescribed range of motion.