An orthopedic brace designed to immobilize the knee by preventing flexion/extension and limiting medial/lateral movement. The brace includes a main support structure embodied in a unitary, rigid stay member with slidable, semi-rigid cuffs at one or both ends to provide length adjustability. The stay member has no popliteal articulation in order to immobilize the knee joint, and further provides attachment for a Velcro strapping system for easy application to the posterior of the leg. A breathable foam softgood insulates the leg and knee from the main support structure and strapping system yet is completely detachable from the brace so it can be trimmed to any desired length or width, and washed as necessary.