PMC:3945237 / 3830-6723
Annnotations
{"target":"https://pubannotation.org/docs/sourcedb/PMC/sourceid/3945237","sourcedb":"PMC","sourceid":"3945237","source_url":"https://www.ncbi.nlm.nih.gov/pmc/3945237","text":"Plain film radiography\nUsing plain film, the sensitivity for detecting early stages of the disease is as low as 41% [3]. Plain film does not detect stage 0 and 1 AVN. A delay of 1-5 years may occur between the onset of symptoms and the appearance of radiographic abnormalities. Normal radiographic findings do not necessarily mean that disease is not present. A staging system using radiographic findings has been developed by Ficat and Arlet and has been used widely for treating avascular necrosis [4]. This has been supplanted by the classification system of Steinberg et al, which incorporates MRI and scintigraphic findings [5].\nIn stage 0 (preclinical and preradiologic) avascular necrosis can be suggested only if it has already been diagnosed in the contralateral hip. Since the advent of MRI, stage 1 (preradiologic) is defined by normal findings on radiographs and positive findings on MRI or bone scintigraphy. Stage 1 represents the early resorptive stage. Late in this stage, plain radiographs may show minimal osteoporosis and/or blurring and poor definition of the bony trabeculae. Stage 2 (reparative) represents the reparative stage before flattening of the femoral head occurs. Stage 2 may extend for several months or longer. Demineralization now is evident. It may be generalized or patchy or appear in the form of small cysts within the femoral head. Patchy sclerosis appears after demineralization develops, usually in the superolateral aspect of the femoral head. In stage 3 (early collapse of the femoral head). A linear subcortical lucency, representing a fracture line, is present immediately beneath the articular cortex. It may extend into the articular cartilage at the superolateral aspect of the femoral head. This is termed the crescent sign (figure 1). Stage 4 (progressive degenerative disease) is represented by further flattening of the femoral head occurs with loss of its smooth convex contour (figure 2). Ultimately, the superior femoral fragment, representing the articular surface and the immediate subchondral bone, may become separated from the underlying femoral head or depressed and compacted into the femoral head. Severe collapse and destruction of the femoral head leads to progressive degenerative joint disease (DJD) with joint space narrowing, marginal osteophyte formation, and subchondral cyst formation.\nFig.1 An anteroposterior pelvic radiography showing flattening of the superolateral aspect (the weightbearing portion) of the right femoral head. There is a zone of decreased density representing the crescent sign, indicating subchondral fracture (stage III)\nFig.2 Anteroposterior radiographyc view of the pelvis shows flattening of the outer portion of the right femoral head from avascular necrosis, with adjacent joint space narrowing, juxta-articular sclerosis, and osteophytes representing degenerative joint disease (stage IV)","divisions":[{"label":"title","span":{"begin":0,"end":22}},{"label":"p","span":{"begin":23,"end":633}},{"label":"p","span":{"begin":634,"end":2359}},{"label":"figure","span":{"begin":2359,"end":2618}},{"label":"label","span":{"begin":2359,"end":2364}},{"label":"caption","span":{"begin":2366,"end":2618}},{"label":"p","span":{"begin":2366,"end":2618}},{"label":"label","span":{"begin":2619,"end":2624}}],"tracks":[{"project":"2_test","denotations":[{"id":"24778812-7822393-24198583","span":{"begin":630,"end":631},"obj":"7822393"}],"attributes":[{"subj":"24778812-7822393-24198583","pred":"source","obj":"2_test"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"2_test","color":"#a293ec","default":true}]}]}}