Anterior cruciate ligament (ACL) injury is a main cause of recurrent knee instability and may result in secondary damages to other structures of the knee, such as meniscal tears and articular cartilage degeneration. The goals of this CEU course are to compare the clinical outcomes between artificial ligaments and autografts, clarify the kinematics of the ACL-deficient knee in squatting motion before and after double-bundle ACL reconstruction, and evaluate the clinical outcome of ACL reconstruction with quadriceps tendon-patellar bone allograft and autograft. In addition, studies are presented exploring pain in the immediate post-operative period after arthroscopic ACL reconstruction, evaluating clinical and radiological results after simultaneous open-wedge high tibial osteotomy and ACL reconstruction, and investigating whether transtibial tunnel technique can achieve anatomical reconstruction of ACL. Lastly, the outcome of single-bundle and double-bundle ACL reconstruction are compared and the hypothesis that suture repair of a ruptured ACL, combined with dynamic augmentation as well as microfracture of the femoral notch is explored in terms of effectiveness compared with that of ACL reconstruction.