A support device provides elevation and support for a patient's foot, including ankle and heal, and limits lateral and medial rotation of the foot. This protects the knee from injury while healing. The device includes a generally flat main body, two spaced-apart lateral ridges, and a medial depression between the lateral ridges that provides a support surface on which the foot may be positioned. The lateral ridges can extend to a height above the support surface so that inner side surfaces of the lateral ridges are adjacent to a majority of a foot placed in the medial depression. The lateral ridges can terminate below a top of the foot to permit unrestricted ventilation and access to the foot. The lateral ridges can be spaced apart to facilitate placement of a foot onto and removal of the foot from the support surface without manual manipulation of the device.