Abstract: An orthosis for passive and active movement of a joint of a body limb, permitting application of adjustable flexion or extension bias to that limb without the application of direct force on the joint. A spaced pair of proximal and distal shafts for medial and lateral positioning about the joint and proximal and distal parts of the limb are provided, these cooperating proximal and distal shafts being joined at a pivot. The pivots are juxtaposed the joint and permit pivoting the distal shafts in a direction corresponding to the direction of movement of the distal part of the limb. Cuff and strap means are secured between opposite proximal and opposite distal shafts to releasably secure the orthosis to proximal and distal parts of the limb. Securing means are associated with portions of the proximal and distal shafts at positions spaced from the pivots.