Three-dimensional analysis of displaced femoral neck fracture and its clinical significance

Abstract

Objective To measure the displacement of the femoral head via three-dimensional reconstruction so as to re-understand the displaced femoral neck fracture. Methods Eighty patients with displaced femoral neck fracture were included in the study including 40 with Garden type Ⅲ and 40 with Garden type Ⅳ fractures. Spiral CT of bilateral proximal femurs was performed along with three-dimensional reconstruction. Displacement parameters of femoral head were determined with three-dimensional measurement technology. Results In cases of Garden type Ⅲ and Ⅳ fractures, displacement of the deepest point of fovea capitis of the femoral head was (23.7±10.0)mm and (30.2±9.0)mm (P<0.05); displacement of femoral head center was (14.4±5.6)mm and (18.8±5.5)mm (P<0.05); femoral head displacement angle was (29.2±15.7)° and (39.1±17.1)° (P<0.05). The incidence of the comminuted fracture was 13% (5/40) among the patients with Garden type Ⅳ fracture. In comparison, no comminuted fracture occurred among the cases of Garden type Ⅲ fracture. Conclusions Three-dimensional reconstruction and digital measurement are precise and efficient methods for the measurement of fracture type and displacement in patients with femoral neck fracture. The present Garden classification for femoral neck fracture has certain defects and limitations. The clinicians should re-understand the displaced femoral neck fracture and choose more reasonable treatment. Key words: Femoral neck fractures; Imaging, three dimensional; Displacement