RESUMEN
[Abstract] Objective To investigate the appropriate X-ray angle which image can represent total proximal of femur according to the anatomic shape of the femoral neck section. Methods The anatomic parameter of the femoral neck section was observed and measured. Found the femoral neck was contained with three main surfaces of anterior surface, posterosuperior surface and posteroinferior surface. A model of surface fluoroscopy has been made by covering aluminum foil papers on the three surfaces of femoral neck. Taking the midpoint of the femoral neck as the fluoroscopy center, the C-arm was rotated at an interval of 10° between 0° and 170°, and the three aluminum foil paper models were taken for X-ray projection respectively. The X-ray angle with the smallest image of aluminum foil paper was taken as the appropriate X-ray angle of the surface. A penetrating model of the femoral neck internal fixation was made of three Kirschner wires penetrating through the anterior, posterosuperior and posteroinferior surfaces of femoral neck. The images of the penetrating Kirschner wires were observed through the traditional anteroposterior, lateral view and the three appropriate X-ray angle views obtained from the above test. Results The length of the three main surfaces accounts for 80. 95% of the circumference of the femoral neck. The anterior surface coronal angle was 18°, the posterosuperior surface coronal angle was 65°, and the posteroinferior surface coronal angle was 165°. The Appropriate X-ray angle of the three surfaces were 20°, 70° and 170° respectively. In the images of the three appropriate X-ray angles, the penetrating Kirschner wires of anterior surface, posterosuperior surface and posteroinferior surface of the femoral neck could be clearly observed respectively, while the penetrating Kirschner wire could not be completely found in the traditional anteroposterior and lateral images. Conclusion Traditional anteroposterior and lateral fluoroscopy can not accurately display the three-dimensional structure of femoral neck. By increasing the appropriate X-ray angle of 20°, 70° and 170°, the reduction quality and bony violation from internal fixation implants on the anterior surface, posterosuperior surface and posteroinferior surface of the femoral neck could be observed respectively.