Abstract: A knee brace for constraining the knee to its natural position and motion includes a femoral band and tibial band connected together by inner and outer rigid bar members pivotally connected together by a floating polycentric hinge joint to permit natural pivoting of the knee and includes a pair of condylar pads for engaging both sides of the knee and a prepatellar pad supported from the condylar pads by derotation straps with further derotation straps securing the prepatellar pad by cross-strap means to opposite ones of the lower bar member. A pair of posterior straps secured to the upper end of the upper bars cross behind the femoral condyles and are connected to opposite ones of the brace hinge members.