Femoral torsion analysis is used to assess the alignment of a femur post surgery. If one side has been operated on it can be compared to the non-operated side.
Superimpose axial images of:
- femoral heads
- the neck of femurs
- femoral condyles
Draw a line from the centre of the femoral head through the axis of the femoral neck, and draw another line along the posterior borders of the femoral condyles. Then measure the angle of these two lines.
Normal antetorsion values are considered to be 15-24°. These calculations and selected points can be very user dependent.