Joint surface geometry based standardization for the ACL insertion by using fuzzy logic

The anterior cruciate ligament (ACL) is one of the important ligaments which control the knee function. In general, the ACL contributes to diminish anteoposterior instability. When some accidents can cause injury of it, the ACL reconstruction is done to recover knee function. The ACL insertion (position of the ACL attachment) is important in the reconstruction, because it determines the knee function after the surgery. Our final goal is to develop a navigation system to provide a criterion of the ACL insertion from information of the condyle shape. The system requires a standardization method of the ACL insertion. Therefore, this study proposes a standardization method by using fuzzy logic to deal with information of the condyle shape. In this experiment, this method was applied for 14 cadaver knees. As a result, the deviation of the angle and distance rate of the ACL insertion on our method were within 13.4 degree and 12.1%, respectively.