Patent ID: 7643868
Filing Date: 2010-01-05
Classification: A61B,G01S

Abstract:
1. Method for determining a position on an upper side of a tibia of an exit point of an implant replacing an anterior cruciate ligament of a knee joint of a leg, in which positional data of the tibia and a femur are determined by means of a navigation system, in which geometrical form data of the femur in a region of the femur facing an upper side of the tibia are recorded and in which the form data are processed together with the positional data of the tibia and the femur in a data-processing system to calculate positional data for the exit point, comprising: with the leg bent, detecting respective positions of a number of points along a front edge of a notch formed by condyles of the femur such that position and progression of the points on the femur are determined, with the leg straight, projecting a course of the front edge of the notch in the form of a curve onto a projection plane which is perpendicular to a longitudinal axis of the tibia in a region of the upper side of the tibia, within a region enclosed by this projected curve, selecting the exit point such that the exit point maintains at least a distance corresponding to a radius of the implant from the projected curve, and selecting a position of the exit point in which the exit point lies as far as possible in a front part of the region enclosed by the projected curve and as close as possible to the projected curve.