[Analysis of the drill hole orientation in anterior cruciate ligament reconstruction]

In the reconstructive procedure of the anterior cruciate ligament (ACL), the relationship was investigated between the orientation of the drill holes from the isometric points and the deformity in the ligament graft. We first investigated, by numerical analysis, the optimal orientation of the drill holes for minimal deformation. Secondly, we experimentally by using eight fresh cadaveric knees, measured the relationship between the orientation of the drill holes and the bending angle in the grafts. The optimal orientation of the drill hole in the femur was found to be tilted 20 degrees laterally in the coronal plane and 23 degrees anteriorly in the sagittal plane. In the tibia, the drill hole should be directed 24 degrees medially and 50 degrees anteriorly from the isometric point. The numerically analysed bending angle corresponded well to the results from the experimental study. The deformation in the graft on the femoral side was larger than that on the tibial side. Therefore, the orientation of the femoral drill hole was concluded to be more important than the orientation of the tibial drill hole.