This invention is an elastic mechanism that extends and retracts during motions of the knee so that it maintains tension in a generally rearward direction on the area of the head of the tibia throughout the range of motion of the knee. The structure is anchored to a stable superior part of the body, above a height of contour, by an attachment which can be a belt, girdle, garment, suspenders or a combination of these attachments. The elastic mechanism attaches inferiorly to a number of connection mechanisms which connect to both sides of a hinged rigid knee brace near the tibial head, below the hinges of the knee brace.