title: Biphasic Analysis of Cartilage Stresses in the Patellofemoral Joint.
abstract: The objective of this study was to examine the state of stress within the solid matrix of articular cartilage in the patellofemoral joint, using anatomically faithful biphasic models of the articular layers, with the joint subjected to physiologic muscle force magnitudes. Finite element models of five joints were created from human cadaver knees. Biphasic sliding contact analyses were performed using FEBio software to analyze the response of the joint from 30 to 60 degrees of knee flexion. Results demonstrated that the collagen matrix always sustains tensile stresses, despite the fact that the articular layers are loaded in compression. The principal direction of maximum solid stresses was consistent with the known orientation of collagen fibrils in cartilage. The magnitudes of these tensile stresses under muscle forces representative of activities of daily living were well below tensile failure stresses reported in the prior literature. Results also hinted that solid matrix stresses were higher in the patellar versus femoral superficial zone. These anatomically correct finite element models predicted outcomes consistent with our understanding of structure-function relationships in articular cartilage, while also producing solid matrix stress estimates not observable from experiments alone, yet highly relevant to our understanding of tissue degeneration.
authors.affiliation: Department of Mechanical Engineering, Columbia University, New York, New York.
authors.forename: Brian
authors.initials: B
authors.lastname: Jones
authors.affiliation: Department of Biomedical Engineering, Columbia University, New York, New York.
authors.forename: Clark T
authors.initials: CT
authors.lastname: Hung
authors.affiliation: Department of Mechanical Engineering, Columbia University, New York, New York.
authors.forename: Gerard
authors.initials: G
authors.lastname: Ateshian
mesh_terms: D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D001696:Biomechanical Phenomena; D002102:Cadaver; D002358:Cartilage, Articular / Q000502:physiology*; D003094:Collagen / Q000502:physiology*; D003198:Computer Simulation; D005260:Female; D020342:Finite Element Analysis; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D057071:Patellofemoral Joint / Q000502:physiology*; D013314:Stress, Mechanical
chemical_list: D003094:Collagen