A cushion can work wonders.
With the ComfortCushion under the thighs, the user maintains a relaxed posture even when the head end of the bed is raised. The cushion prevents the patient from sliding down in bed. With the cushion placed under the knees, the pressure on the legs is relieved, giving a pleasant sense of relaxation.
The material in the cushion is soft enough to be yielding and at the same time firm enough to provide support.