Change of Femoral Anteversion during Closed Femoral Intramedullary Nailing / 대한정형외과학회잡지

ABSTRACT

Average anteversion of the femur is 15.3 degree. Ultrasound, computerized tomogram, and three dimensional reconstruction from CT or MRI have been used for more accurate measurement of the anteversion. There are two methods in measuing anteversion angle from CT scanone is by drawing a mid line through long axis of the femoral neck (conventional method). Another is by drawing a line from the center of the head to that of the neck at the base of the trochanter using several cut slices (Murphy’s method). We compared these methods with fluoroscopic measurement of the Anteversion. We traced the change of the anteversion before and after closed femoral intramedullary (IMO) nailing to evaluate the origin of malrotation of the femur. 1. Normal anteversion angles were measured in 15 cases. Average anteversion angle was 6.9 degrees by conventional method, 12.3 degrees by Murphy’s method, and 12.2 degrees by fluoroscope. 2. Anteversion angles were measured after IM nailing in 18 cases. Average was 17 degrees by Murphy’s method and 15.2 degrees by fluoroscope. Mean of difference between these two methods sea 6.3 degrees. That was 1.7 degrees in normal side. 3. Change of the anteversion angle between before and after IM nailing was measured in 17 cases by fluoroscope. Average anteversion angle before the operation was 11.9 degrees and it was change to 15.8 degrees after operation. Mean of these change was 7.1 degrees. 4. Pereperative traction provides important information on change of anteversion. Reduction excessive flexion of proximal fragment was a origin of change of anteversion during nailing procedure. Conclusion: Malrotation of the femur after IM nailing must be keep in mind and it may be preventable by fluoroscopic control of the rotation in nailing procedure.