Abstract: The invention relates to an orthesis for controlling the angle of a limb relative to a second body part to which the limb is connected via a joint such as a hip, elbow or shoulder, which orthesis comprises:—a first arm rotatably, around a rotation point, connected to the second body part;—a second arm fixedly arranged to the lim; and—guide means for providing at least a two dimensional free translation of the second arm relative to the first arm, while maintaining both arms parallel.