A device for increasing the range of motion of a patient's knee joint generally includes a frame, a lever member pivotally coupled to the frame at a first location, and an actuator pivotally coupled to the frame at a second location. The frame supports the patient in a manner that allows motion of the patient's knee joint, and the lever member bears against a portion of the patient's body below the knee joint. The actuator is also pivotally coupled to the lever member. When operated by a controller, the actuator generates a translational input that rotates the lever member relative to the frame and thereby stretches the patient's knee joint in a desired direction.