Read Aloud the Text Content

This audio was created by Woord's Text to Speech service by content creators from all around the world.

Text Content or SSML code:

If history and physical examination findings are suspicious for ONFH, plain radiography is the next step in diagnosis. Although very early ONFH may be undetectable on plain radiography, early ONFH shows, on anteroposterior pelvis and frog lateral views, cystic and or sclerotic changes in the femoral head . The term, crescent sign, describes an area of subchondral lucency in the femoral head that indicates subchondral fracture due to bone necrosis and subsequent attempts at repair ONFH at a later stage shows femoral head flattening, collapse, and degenerative changes . MRI is the modality of choice for patients with a suspicious history and physical examination with normal radiographs. It is 99% sensitive and specific for detecting early ONFH, which usually presents as an area of low-intensity signal on T1-weighted and high-intensity signal on T2-weighted images. Bone marrow edema and a joint effusion also may be present. The later stages of ONFH are better followed using plain radiography and, in some cases, CT scan. In conclusion, plain radiography should be used for initial evaluation of suspected ONFH as well as after disease progression in the later stages, with MRI to be used in the setting of normal radiographs with suspicious history and or examination findings.