Quality of reduction and cortical screw support in femoral neck fractures. An analysis of 72 fractures with a new computerized measuring method.

The aim of this study was to compare the quality of reduction and the position of the fixating screws with the rate of union in 72 femoral neck fractures. The degree of fracture displacement after reduction and the position of the two fixating screws were determined with a new computerized measuring method that compensates for the variations in hip rotation in routine radiographs. All 13 nondisplaced fractures united. Sixteen of 18 fractures healed in the group of displaced fractures where both the fixating screws were placed within 3 mm from the femoral neck cortex, compared with 13 of 22 healed fractures in the group where only one screw had the same close contact with the femoral neck cortex (p < 0.05). Nonunion developed in all five displaced fractures where none of the two fixating screws were placed within 3 mm from the femoral neck cortex. The quality of reduction did not affect the healing rate; however, the number of poorly reduced fractures was only 10%. The results of this study underline the importance of achieving cortical support for the fixating screws in femoral neck fracture surgery.