Abstract:
This study addresses a critical gap in understanding the local biomechanics of the knee following Anterior Cruciate Ligament (ACL) reconstruction, specifically focusing on how graft size influences joint stability and the propensity for soft tissue injury. Despite the frequent performance of ACL reconstructions, quantitative biomechanical data, particularly concerning graft size, has been limited. To systematically investigate this relationship, a non-linear contact finite element model of the knee was developed. This model was then utilized to simulate a Lachman maneuver, allowing for the assessment of various key biomechanical parameters including knee joint laxity, meniscal stress, in situ graft loading, and peak articular cartilage contact pressure across a range of ACL graft sizes (5 to 9 mm), as well as in an ACL-deficient knee. The model's validity was rigorously established through corroboration with previously published experimental cadaveric data on ACL reconstruction. The results demonstrated that a 5 mm graft led to a 30% greater relative anterior-posterior (AP) translation compared to a 9 mm graft, while an ACL-deficient knee exhibited a 2.56-times greater AP translation than the average graft reconstruction. Furthermore, contact pressure and peak meniscal stresses decreased monotonically with increasing graft size, with the 9 mm graft showing the lowest values across all biomechanical metrics. The in situ graft loading exhibited an exponential increase with increasing graft size. These findings underscore the significant impact of ACL graft size on the biomechanical environment of the reconstructed knee, providing crucial insights for optimizing surgical strategies to enhance joint stability and minimize the risk of subsequent soft tissue complications.
