Subchondral Insufficiency Fracture of the Femoral Head: Magnetic Resonance Imaging Findings Correlated With Micro–Computed Tomography and Histopathology

We described magnetic resonance (MR) imaging findings of subchondral insufficiency fracture of the femoral head without collapse in which micro-computed tomography (CT) and histopathologic studies were performed. Magnetic resonance imaging showed a subchondral low-signal intensity band, which corresponded to the fracture callus. Diffuse bone marrow edema with contrast enhancement effect was seen in both the proximal and distal segments of the low-signal intensity band. These features are distinct from those of avascular necrosis.