Analyze 3-D Knee Kinematics after Anterior Cruciate Ligament Reconstruction Using MDCT and Digital Radiography

Rupture of anterior cruciate ligament (ACL) is a serious problem which causes in functional stability of the knee joint. To restore the knee injury, surgical operations, which replace the damaged ACL, have been applied. After ACL reconstruction, it is important to numerically evaluate the knee kinematics to diagnose the ACL reconstruction patients and to evaluate ACL reconstruction operation techniques. There are a few methods for analyzing 3-D knee kinematics based on image registration of multidetector-row CT (MDCT) and digital radiography (DR). However, estimation accuracy depends on the given initial pose/position by user-interactions. This paper proposes a fully-automated method for analyzing 3-D knee kinematics using MDCT and DR. The method firstly performs rough 3-D pose/position recognition with respect to anatomical landmarks, and secondly performs fine-image registration using digitally reconstructed radiography (DRR) images generated from MDCT images. Thus, the method requires no user-interaction. Performance of estimating 3-D knee kinematics was evaluated by using computer-synthesized images and subject's DR image.