A joint device is provided for treating a patient who is unable to flex and extend an arm, leg or other jointed member through its normal range of movement about the patient's joint. The joint device includes two extending sidearms. Each sidearm is secured by a sleeve, cast, brace or the like to the patient's limb so that the sidearms are on opposite sides of the afflicted joint. The joint device pivotally connects the two sidearms, and includes a selectively actuated one-way clutch which allows movement in one direction while inhibiting it in the other.