A polycentric hinge is positioned on one side of the patient's knee and a unicentric hinge is positioned on a second side of the knee. A lower portion of the polycentric and unicentric hinge is attached to a knee cuff about a lower leg of the patient. An upper arm of the polycentric and unicentric hinge is attached to a thigh cuff, the upper arm of the unicentric hinge being longer than the upper arm of the polycentric hinge. The upper arm of the unicentric hinge has a 15.degree. to 20.degree. set back angle when the patient's leg is straight. The polycentric hinge has a slotted central plate with star gears engaging a back portion and multiple movable blocks mounted in screw holes on a front edge of the slotted plate supporting an elastic band having a fulcrum point on the polycentric hinge at a lower and upper end.