Effect of ACL Reconstruction Graft Material on Joint Force Loss During Cyclic Fatigue Testing Using a 6-DOF Motion

As many as 250,000 people suffer anterior cruciate ligament (ACL) injury annually [1]. As the primary ligamentous restraint to anterior tibial translation [2–3], the ACL is surgically reconstructed in an attempt to restore knee stability. However, up to 10–25% of reconstructions still fail [4]. While reconstructions restore antero-posterior kinematics, abnormal kinematics persist in other directions [5], leading to a shift in cartilage contact and poor adaptation to altered load [5]. With or without reconstruction, the likely prognosis after ACL injury is long-term osteoarthritis [6]. Improving this outcome requires assessment of the limitations of ACL graft reconstruction compared to normal ACL forces during simulated activities of daily living (ADLs). Our objective in this study was to evaluate the magnitude and temporal changes in force for the intact versus ACL-reconstructed knee over 2000 cycles of a simulated ADL.