Stress Fracture

Etiology: repetitive microtrauma to normal bone
Radiograph: fracture represented by lucency, may see marked cortical thickening in area of injury
MRI: periosteal + marrow edema, may show fracture line
DDX: Ewing sarcoma, no extra osseous soft tissue mass favors stress fracture over Ewing sarcoma

Cases of Stress Fracture

Radiograph of stress fracture of the femur — AP and lateral radiographs of the femur show on the AP view a transverse non-displaced healing fracture through the distal femoral diaphysis that on the lateral view has periosteal reaction and marked cortical thickening along the posterior aspect of the femur.

Radiograph of stress fracture — AP radiograph of the foot obtained at presentation (left) shows a mild amount of perisoteal reaction around the diaphysis of the second metatarsal that is much better seen on the repeat radiograph from 1 month later (right).