It usually occurs later in the disease, in stage III of the four-stage Ficat classification system. It appears as a curved subchondral radiolucent line that is  often found on the proximal femoral or humeral head.
This condition usually appears in a later phase of the disease, according to the four-stage Ficat classification system. It typically takes the form of a curved subchondral radiolucent line that is frequently seen on the proximal femoral or humeral head.