An orthosis for extension and flexion of a joint of a limb provides for distraction of the joint upon extension. In one embodiment, a spreading arrangement positively moves the orthosis arms longitudinally outwardly relative to each other upon rotation from a flexed position to an extended position. In another embodiment, the axis of rotation of the orthosis arms is located outwardly from the axis of rotation of the limb. Upon rotation of the arms relative to each other from a flexed position to an extended position, the orthosis arms move longitudinally outwardly because of the geometry of the orthosis. Because the cuffs on the arms are clamped to the limb segments, the limb segments are also forced outwardly, providing joint distraction. Structure is provided for limiting the amount of joint distraction and avoiding injury to the joint.
The inner ends of the orthosis arms are linked together to maintain them in position relative to each other. The cuffs which attach the arms to the limb segments are adjustable longitudinally along the arms, to provide for different positions of the cuffs on the on limb, different length limbs, and the use of the orthosis on either a knee joint or an elbow joint.