title: Three dimensional patient-specific collagen architecture modulates cartilage responses in the knee joint during gait.
abstract: Site-specific variation of collagen fibril orientations can affect cartilage stresses in knee joints. However, this has not been confirmed by 3-D analyses. Therefore, we present a novel method for evaluation of the effect of patient-specific collagen architecture on time-dependent mechanical responses of knee joint cartilage during gait. 3-D finite element (FE) models of a human knee joint were created with the collagen architectures obtained from T2 mapped MRI (patient-specific model) and from literature (literature model). The effect of accuracy of the implementation of collagen fibril architecture into the model was examined by using a submodel with denser FE mesh. Compared to the literature model, fibril strains and maximum principal stresses were reduced especially in the superficial/middle regions of medial tibial cartilage in the patient-specific model after the loading response of gait (up to -413 and -26%, respectively). Compared to the more coarsely meshed joint model, the patient-specific submodel demonstrated similar strain and stress distributions but increased values particularly in the superficial cartilage regions (especially stresses increased >60%). The results demonstrate that implementation of subject-specific collagen architecture of cartilage in 3-D modulates location- and time-dependent mechanical responses of human knee joint cartilage. Submodeling with more accurate implementation of collagen fibril architecture alters cartilage stresses particularly in the superficial/middle tissue.
authors.affiliation: a Department of Applied Physics , University of Eastern Finland , Kuopio , Finland.|b Diagnostic Imaging Centre, Kuopio University Hospital , Kuopio , Finland.
authors.forename: Lasse P
authors.initials: LP
authors.lastname: Räsänen
authors.affiliation: a Department of Applied Physics , University of Eastern Finland , Kuopio , Finland.
authors.forename: Mika E
authors.initials: ME
authors.lastname: Mononen
authors.affiliation: c Department of Diagnostic Radiology , Oulu University Hospital , Oulu , Finland.|e Medical Research Center, University of Oulu and Oulu University Hospital , Oulu , Finland.
authors.forename: Eveliina
authors.initials: E
authors.lastname: Lammentausta
authors.affiliation: c Department of Diagnostic Radiology , Oulu University Hospital , Oulu , Finland.|d Department of Radiology , Institute of Diagnostics, University of Oulu , Oulu , Finland.|e Medical Research Center, University of Oulu and Oulu University Hospital , Oulu , Finland.
authors.forename: Miika T
authors.initials: MT
authors.lastname: Nieminen
authors.affiliation: a Department of Applied Physics , University of Eastern Finland , Kuopio , Finland.|b Diagnostic Imaging Centre, Kuopio University Hospital , Kuopio , Finland.
authors.forename: Jukka S
authors.initials: JS
authors.lastname: Jurvelin
authors.affiliation: a Department of Applied Physics , University of Eastern Finland , Kuopio , Finland.|b Diagnostic Imaging Centre, Kuopio University Hospital , Kuopio , Finland.
authors.forename: Rami K
authors.initials: RK
authors.lastname: Korhonen
mesh_terms: D000328:Adult; D002358:Cartilage, Articular / Q000502:physiology*; D003094:Collagen / Q000378:metabolism*; D020342:Finite Element Analysis; D005684:Gait / Q000502:physiology*; D006801:Humans; D021621:Imaging, Three-Dimensional; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008297:Male; D016062:Porosity; D013314:Stress, Mechanical
chemical_list: D003094:Collagen
keywords: Articular cartilage; collagen architecture; finite element analysis; knee joint; magnetic resonance imaging; submodeling