Because hip joints are distal and anterior to X, rotary and posterior bending forces, in addition to forces in coronal plane, are applied and tend to rotate and bend prosthetic stem.

• 由于髋关节在X点前方，而且距离较远，除冠状面的应力外，易受到旋转力和后屈力的作用，故有使假体柄发生旋转和弯曲的趋势。