Fig. 2. With the rotation axis Z, varus osteotomy results in the change of three-dimensional location of femoral head.
X coordinate is increased (x0<x1), Y coordinate is decreased (y0>y1), and Z coordinate is not changed (z0=z1). Therefore, angle of valgus and anteversion is decreased (v0>v1,γ0>γ1) and flexion angle (β0<β1) is increased.
H0 and H1: Center of femoral head before and after varus osteotomy.
v0 and v1: the valgus angle before and after varus osteotomy.
β0 and β1: the flexion angle before and after varus osteotomy.
γ0 and γ1: the angle of anteversion before and after varus osteotomy.