Corticosteroid-induced Osteonecrosis of the Femoral Head: Detection, Diagnosis, and Treatment in Earlier Stages

Liu, Li-Hua; Zhang, Qing-Yu; Sun, Wei; Li, Zi-Rong; Gao, Fu-Qiang

Plain radiograph examination is the most convenient diagnostic modality and widely used to depict femoral head morphological changes. These changes are characteristics based on the pathology of sclerosis band, cystic change, and crescent sign in a subchondral location. However, plain radiograph examination lacks sensitivity in early-stage diseases compared with MRI with a diagnostic window between the onset of symptoms and the appearance of pathognomonic changes. Computerized tomography (CT) is not routinely applied in early-stage lesions. CT plays an important role in detecting subchondral fractures without an apparent focal collapse and in decreasing false-positive diagnosis of MRI findings. CT is also used to detect bone repair and degree. Generally, bone scan is the modality of choice for an early diagnosis but is less specific than MRI in identifying early-stage ONFH. Other modalities may be useful in particular conditions but still need to be validated for the early diagnosis of ONFH.