Osteonecrosis Imaging

Osteonecrosis is ischemia of bone due to inadequate vascular supply. This condition results in bone tissue death and loss of structural integrity. If left untreated, it can lead to bone collapse. This condition is also known as avascular necrosis or aseptic necrosis when it involves the epiphysis and as bone infarct when it involves metadiaphyseal regions of bone. Osteonecrosis is common and typically asymptomatic in its early stages. This condition affects various bones in the body, including hips, knees, shoulders, ankles, and small bones of hands and feet. Some of the most common causes of osteonecrosis include chronic corticosteroid use, alcohol use disorder, trauma, and idiopathic causes. Other common predispositions include systemic diseases such as sickle cell anemia and collagen vascular disease.  Osteonecrosis may be asymptomatic in its early stage. This condition can also present with limited movement, inability to bear weight, significant pain, and swelling of the affected joint. Recognizing various presentations of osteonecrosis is crucial. In addition, understanding when and what further necessitates evaluation is important. When osteonecrosis involves the small bones of hands and feet or epiphysis of long bones, it is essential to assess the risk of secondary complications such as subchondral collapse. Imaging modalities used to evaluate osteonecrosis include plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and nuclear medicine studies. However, knowing which modality is most sensitive at a certain point in the patient's clinical presentation and when it is necessary is crucial. Early diagnosis and treatment of osteonecrosis affecting epiphyseal locations remains the key to joint preservation.