Patent ID: 8257360
Filing Date: 2012-09-04
Classification: A61B

Abstract:
1. A method for determining a distal cut thickness and posterior cut thickness for a femur in a knee replacement operation, the method comprising: performing a tibial cut on a tibia; performing soft tissue balancing based on a desired limb alignment; creating a reference coordinate system in a computer aided surgery system for an uncut femur and said tibia; registering said femur and said tibia to said reference coordinate system using tracking devices; measuring an extension gap between said femur and said tibial cut while in extension using said femur and tibia as registered in said reference coordinate system; measuring a flexion gap between said femur and said tibial cut while in flexion using said femur and tibia as registered in said reference coordinate system; calculating a distal cut thickness and a posterior cut thickness for said femur using said measured extension gap and said measured flexion gap and taking into account a distal thickness and posterior thickness of a femoral implant; and performing said femoral posterior cut according to said posterior cut thickness subsequently to the calculating of the posterior cut thickness; and performing said femoral distal cut according to said distal cut thickness and based on the flexion gap resulting from the performed femoral posterior cut registered in said reference coordinate system.