The Kinematic Basis of ACL Reconstruction

The goals of anterior cruciate ligament (ACL) reconstruction are to restore knee stability and function and to preserve joint health. Static tests for antero-posterior laxity (e.g. Lachman test or KT-1000 arthrometer) have typically shown restoration of normal or near-normal laxity with a variety of modern ACL reconstruction techniques. However, ACL reconstruction has failed to prevent early onset of osteoarthritis, and there is growing evidence that traditional single-bundle ACL reconstruction does not restore normal knee mechanics under functional loading conditions. ACL reconstruction may fail to restore normal rotational stability during the pivot shift. Abnormal internal-external rotation and ab/adduction have been reported after ACL reconstruction during normal daily activities like walking and running. Recently, cadaveric studies have shown the potential superiority of ACL double bundle (DB) reconstruction for restoring anatomy and mechanical function. However, clinical data demonstrating the clear superiority of DB reconstruction is lacking, due to the absence of well-controlled clinical studies. Additionally, dynamic knee function after anatomic DB ACL has yet to be assessed comprehensively.