An analysis method of endobutton position with registration in MDCT images after anterior cruciate ligament reconstruction

ACL (Anterior Cruciate Ligament) reconstruction is performed to recover the injured knee which often happens in sports activity such as skiing, and basketball. The ACL reconstruction makes one or two bone tunnel(s) in the femur and tibia. Then, the harvested graft passes the bone tunnels so that the femur and tibia are connected. The graft is fixed to the femur by using EndoButton. However, loosening of the fixation sometimes happens due to transposition of the EndoButton. It results in instability of the knee motion. Occurrence frequency of the fixation loosening affects clinical outcome. Therefore, it is important to analyse an EndoButton position with high accuracy. This study set the goal to propose an analysis method of the EndoButton position with registration in MDCT images. In the experiments, the proposed method was applied to 5 (single bundle) and 8 (double bundle) sets of MDCT images. Each set consists two different direction posing of the same patient in one day. EndoButton of AM shows a distinctive time-depend movement. the EndoButton flexion movements of single and AM increase with time. As a result, the proposed method could calculate the EndoButton position with registration in MDCT images.