Determination of femoral anatomic axis in robot-assisted surgery of total knee replacement / 生物医学工程学杂志

ABSTRACT

Determination of femoral anatomic axis plays an important role in robot-assisted surgery of total knee replacement. In traditional total knee replacement surgery, the axis is obtained by inserting a rod into femoral lumen. However, in the robot-assisted total knee replacement based on CT model. the femoral anatomic axis must be determined preoperatively. Because the lengths in femurs are quite different in different patients, besides noises, the upper segment and lower segment of the femur influence the design of the axis greatly. Traditionally, the femoral anatomic axis is obtained by using the least-squares method directly. However, this method is easily disturbed by noise. To avoid the noise disturbance of CT data, the least median of squares method is used to fit the femoral anatomic axis for its characteristic of robust regression. The least median squares method eliminates the disadvantage brought by the method of least squares. In finding the best-fit line, genetic algorithms are used in the paper. In our experiment, we use the proposed method to fit the femoral anatomic axis and obtain an excellent result.