Validation of an in vivo 3d knee joint laxity model

Abstract

A numerical knee joint laxity model [1] was previously developed based on an in vivo measurement of knee joint laxity using the KLA and MR imaging [2] to enhance the understanding of the contribution of knee joint structures to passive knee joint stability. The credibility of the verified knee joint laxity model was assessed through an in vitro experimental setup by testing cadaveric specimens in an in situ knee loading apparatus (ISKLA) during MR imaging (for numerical model inputs), along with an ElectroForce test system (for direct measurement of individual ligament and contact forces). The model was found to overestimate the ACL forces by 27.61 %-92.71 %. The validation of force-displacement curves obtained from numerical analysis of MR image bony geometry was a key contribution of this study, particularly to the overall project goals of developing an in vivo laxity tool, with MR-based displacements and stiffness values found to be within 19.02%-26.75% and 13.42%-39.06% of direct experimental measurements.