Patent ID: 7427272
Filing Date: 2008-09-23
Classification: A61B,A61F

Abstract:
1. A method for determining a mechanical axis of a femur using a computer aided surgery system having an output device for displaying said mechanical axis, the method comprising: providing a position sensing system having a tracking device capable of registering instantaneous position readings and attaching said tracking device to said femur; locating a center of rotation of a femoral head of said femur by moving a proximal end of said femur to a first static position, acquiring a fixed reading of said first static position, repeating said moving and said acquiring for a plurality of static positions; and locating said centre by determining a central point of a pattern formed by said plurality of static positions; digitizing an entrance point of said mechanical axis at a substantially central position of said proximal end of said femur; joining a line between said entrance point and said center of rotation to form said mechanical axis; and displaying said mechanical axis on an output device without reference to an image of said femur acquired pre-operatively or intra-operatively using a medical imaging device.