Subchondral stress fractures of the femoral head associated with military training: Clinical features and analysis

Figure 3 Representative X-ray and magnetic resonance imaging findings of subchondral stress fracture of the femoral head across the predefined imaging stages. A and E: Stage I: Mild articular-margin depression with localized magnetic resonance imaging bone marrow edema; B and F: Stage I: Mild articular-margin depression with an indistinct fracture line and joint effusion; C and G: Stage II: Obvious articular depression with a clear subchondral fracture line, marked effusion, and extensive bone marrow edema; D and H: Stage III: Femoral-head flattening and advanced degenerative change with less prominent bone marrow edema. The staging framework was adapted from previously described imaging features[6,9].