Fig. 2.

A 52‐year‐old man had nonunion of femur fracture, after internal fixation with three cannulated screws by traditional procedure. (A) Preoperative anteroposterior (AP) and lateral hip X‐ray images; (B) postoperative AP and lateral hip X‐ray images, which show that the cannulated screws are parallel but not spread. (C) Three months after the operation, the fracture had not healed and the screw began slipping. (D) 12 months after the operation, the bone of the femoral neck resorbed and the femoral head was displaced again.