PMC4159374_01
Radiograph of the left hip joint at 12 months after the onset of pain. The anteroposterior view shows vertical sclerosis running from the top of the femoral head to the femoral neck (black arrow). A lesion inside the boundary demonstrates diffuse sclerosis. Medial joint space narrowing is also apparent (white arrow).
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A radiograph obtained 12 months after the onset of pain showed vertical sclerosis in the center of the femoral head, and the lesion inside the boundary demonstrated diffuse bony sclerosis (Fig. 1).
MRI images at 12 months after the onset of pain. (A) T1 images (reception time/echo time [TR/TE] 570/12 ms). The coronal image shows a vertical low-intensity band (white arrow) in the femoral head. (B) Fat-saturated T2 images (reception time/echo time [TR/TE] 4000/104 ms). In the coronal plane, the lesion demonstrates a diffuse high signal intensity.
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T1-weighted magnetic resonance imaging (MRI) showed a vertical low-intensity band corresponding to the sclerotic rim on the radiograph (Fig. 2A). On fat-saturated T2-weighted images, a diffuse high-intensity area was observed within the medial lesion (Fig. 2B).
CT images (2-mm slices) at 12 months after the onset of pain. (A) The coronal image shows vertical sclerosis (black arrow). Collapse is suspected at the inferomedial portion (white arrow). (B) On the axial image, collapse (white arrow) is seen at the anteromedial portion.
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Computed tomography (CT) showed a subchondral collapse at the medial lesion (Fig. 3A, 3B).
A biopsy specimen obtained using a 6-mm diameter biopsy needle. The (B) area shows the osteosclerotic demarcation dividing the medial osteonecrotic lesion (A) and lateral normal bone (C).
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A biopsy specimen (Fig. 4) was obtained to confirm the diagnosis, using a 6-mm diameter biopsy needle that was advanced from the distal portion of the greater trochanter to the medial lesion of the femoral head.
Histological appearance of the femoral head (hematoxylin and eosin staining, 40x). Osteonecrotic bone trabeculae (ON) show empty lacunae (black arrows) and are surrounded by vascularized fibrous tissue in combination with appositional bones (AB).
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Histologically, osteonecrotic bone trabeculae covered by appositional bone formation were seen within the lesion (Fig. 5), and the bone marrow tissue contained vascular-rich fibrous tissues.