Our patented asymmetrical eight sphere, four bar hinge mechanism is the only hinge available that actually tracks the natural changing center of rotation of the knee joint. This helps to keep the brace from "cater-pillaring" up, or down the leg during flexion and extension. This hinge design also allows for a 10mm lateral shift, which gives the lower frame automatic tibia alignment, allowing it to accurately capture the tubercle (top of the shinbone). Having an asymmetrical hinge allows the frame to follow closer to the inner side of the leg, keeping the frame set up against the tubercle, thus effectively capturing it. The hinge allows for extension regulation between 0° and 40°.