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[Discerning the femoral neck anteversion (FNA) from the torsion angle on 3D CT]
Qiu-Liang Zhu1, Jian-Feng Yuan, Li-Lai Zhao
1Department of Orthopaedics, the People's Hospital of Anji, Huzhou 313300, Zhejiang, China. zhuqiuliang666@163.com
Objective:
To discern the differences between femoral neck anteversion (FNA) and torsion angle through 3D CT reconstruction.
Methods:
From March 2010 to October 2010,30 healthy adult volunteers' femur were reconstructed by 3D CT, included 15 males and 15 females with an average age of (43.66 +/- 7.57) years old ranging from 25 to 65 years. Display the FNA and the torsion angle by image post-processing, measuring torsion angle by "Center way" and direct measurement of FNA.
Results:
FNA was the angle between the axle wire of femoral neck and the shape face of femoral,the angle were (13.326 +/- 6.085) degrees. Torsion angle was the angle between the macropinacoid of cross section of femoral neck and the shape face of femoral, the angle were(31.335 +/- 2.079) degrees. There was no significant difference in left and right femur.
Conclusion:
FNA is different from torsion angle. FNA is the angle between the line and the surface with the sharp angle towards the lower outside. The torsion angle is the angle between the two surfaces with the sharp angle towards the lower back.
