Osteochondritis Dissecans result in abnormal, damaged cartilage at the top of the talus bone. It is often a result of a traumatic injury, such as a severe ankle sprain but can happen with chronic overuse or overloading of the foot. These symptoms often affect different regions of the tarsal. Surgery is performed to remove any debris from the area. Cartilage grafts may also be used to try to repair the injury during surgery.