Background: Anterior cruciate ligament (ACL) injury causes knee instability which affects
sports activity involving cutting and twisting motions. The ACL reconstruction surgery replaces
the damaged ACL with artificial one which is fixed to the bone tunnels opened by the surgeon.
The outcome of the ACL reconstruction is strongly related to the placement of the bone tunnels,
therefore, the optimization of tunnel drilling technique is an important factor to obtain satisfactory
surgical results. The quadrant method is used for the post-operative evaluation of the ACL
reconstruction surgery, which evaluates the bone tunnel opening sites on the lateral 2-D X-ray radiograph.
Method: For the purpose of applying the quadrant method to the pre-operative knee MRI, we have
synthesized the pseudo lateral 2-D X-ray radiograph from the patients' knee MRI. This paper proposes
a computer-aided surgical planning system for the ACL reconstruction. The proposed system
estimates appropriate bone tunnel opening sites on the pseudo lateral 2-D X-ray radiograph synthesized
from the pre-operative knee MRI.
Results: In the experiment, the proposed method was applied to 98 subjects including subjects with
osteoarthritis. The experimental results showed that the proposed method can estimate the bone
tunnel opening sites accurately. The other experiment using 36 healthy patients showed that the
proposed method is robust to the knee shape deformation caused by disease.