A joint brace comprises a first frame adapted to be secured onto a body part on the first side of a joint, a second frame adapted to be secured onto a body part on the other side of a joint, a hinge mechanism connecting the first frame to the second frame so the first frame and the second frame can rotate relative to one another about a hinge axis that is adapted to be generally aligned with the axis of rotation of the joint, and a bias system that biases the first frame away from the second frame and towards an extended position. In one version, the bias is applied for more than about 30 degrees of flexion of the first frame relative to the second frame. In another version, is removable so that it can be selectively installed and removed by the user.
