Abstract
Introduction
The treatment of trochanteric femoral fractures with the use of short femoral nails has become an established method. The fixation is required that lag screw be centered to prevent complications. But correct positioning of the device may difficult because of anatomical feature. This study evaluated the femoral morphology three-dimensionally using computed tomography (CT) images.
Methods
Seventy eight patients (mean age 75)who underwent total knee arthroplasty were included. After three-dimensional reconstruction of the CT images, the anterior deviation from the femoral neck axis to proximal shaft axis was measured. The proximal shaft axis was defined as a line between center of the cross-section underneath the lesser trochanter and the center of diaphysis. The connection of center in narrow section of the neck and femoral head center was defined as neck axis.
Results
The femoral neck axis and shaft axis were not coplanar. The anterior deviation of the axes was 7.5 mm (1.7 to 18.4 mm). The neck-shaft angle was 124° (110–142°).
Discussion
Our results indicate that the nail and screw could not be center in current nail system, because of the non-crossing of the femoral axes. The large variation of neck-shaft angle would lead error in preoperative planning using traditional 2-D template system. Our study suggests needs for three-dimensional template system and newly femoral nail device.
