Osteonecrosis

Death of a fragment of bone tissue due to an interruption in blood circulation, resulting in bone infarction. The bone trabeculae of the dead tissue are no longer renewed and eventually collapse. If osteonecrosis affects a joint area, the joint becomes deformed and painful. Osteonecrosis can affect all joints, particularly the femoral head, humeral head and medial condyle (lower end) of the femur.