Symptoms of Osteonecrosis
Pain, the earliest symptom of ON, may occur in the early stages of involvement, before any radiographic changes are noted. This pain is likely to be the result of elevated intraosseous pressure because such pain can be relieved by decompression. In some individuals, no symptoms develop until the late stages of the disease process when collapse of the articular surface occurs and secondary degenerative changes develop. Others, in whom the area of infarction is small enough that collapse does not occur, may never develop symptoms. Radiographs in these patients reveal sclerotic areas often referred to as “bone islands” or “bone infarcts.”