title: Quantifying in vivo laxity in the anterior cruciate ligament and individual knee joint structures.
abstract: A custom knee loading apparatus (KLA), when used in conjunction with magnetic resonance imaging, enables in vivo measurement of the gross anterior laxity of the knee joint. A numerical model was applied to the KLA to understand the contribution of the individual joint structures and to estimate the stiffness of the anterior-cruciate ligament (ACL). The model was evaluated with a cadaveric study using an in situ knee loading apparatus and an ElectroForce test system. A constrained optimization solution technique was able to predict the restraining forces within the soft-tissue structures and joint contact. The numerical model presented here allowed in vivo prediction of the material stiffness parameters of the ACL in response to applied anterior loading. Promising results were obtained for in vivo load sharing within the structures. The numerical model overestimated the ACL forces by 27.61-92.71%. This study presents a novel approach to estimate ligament stiffness and provides the basis to develop a robust and accurate measure of in vivo knee joint laxity.
authors.affiliation: a Department of Mechanical and Manufacturing Engineering, Schulich School of Engineering , University of Calgary , Calgary , Canada .
authors.forename: L M
authors.initials: LM
authors.lastname: Westover
authors.affiliation: a Department of Mechanical and Manufacturing Engineering, Schulich School of Engineering , University of Calgary , Calgary , Canada .
authors.forename: N
authors.initials: N
authors.lastname: Sinaei
authors.affiliation: a Department of Mechanical and Manufacturing Engineering, Schulich School of Engineering , University of Calgary , Calgary , Canada .
authors.forename: J C
authors.initials: JC
authors.lastname: Küpper
authors.affiliation: a Department of Mechanical and Manufacturing Engineering, Schulich School of Engineering , University of Calgary , Calgary , Canada .|b McCaig Centre for Bone and Joint Health , University of Calgary , Calgary , Canada .
authors.forename: J L
authors.initials: JL
authors.lastname: Ronsky
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016118:Anterior Cruciate Ligament / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology*; D008279:Magnetic Resonance Imaging; D009716:Numerical Analysis, Computer-Assisted; D015203:Reproducibility of Results; D055815:Young Adult
keywords: Knee joint; anterior cruciate ligament; numerical modelling; passive laxity