title: Analyzing the anisotropic Hooke's law for children's cortical bone.
abstract: Child cortical bone tissue is rarely studied because of the difficulty of obtaining samples. Yet the preparation and ultrasonic characterization of the small samples available, while challenging, is one of the most promising ways of obtaining information on the mechanical behavior of non-pathological children׳s bone. We investigated children׳s cortical bone obtained from chirurgical waste. 22 fibula or femur samples from 21 children (1-18 years old, mean age: 9.7±5.8 years old) were compared to 16 fibula samples from 16 elderly patients (50-95 years old, mean age: 76.2±13.5 years old). Stiffness coefficients were evaluated via an ultrasonic method and anisotropy ratios were calculated as the ratio of C33/C11, C33/C22 and C11/C22. Stiffness coefficients were highly correlated with age in children (R>0.56, p<0.01). No significant difference was found between C11 and C22 for either adult or child bone (p>0.5), nor between C44 and C55 (p>0.5). We observe a transverse isotropy with C33>C22=C11>C44C55>C66. For both groups, we found no correlation between age and anisotropy ratios. This study offers the first complete analysis of stiffness coefficients in the three orthogonal bone axes in children, giving some indication of how bone anisotropy is related to age. Future perspectives include studying the effect of the structure and composition of bone on its mechanical behavior.
authors.affiliation: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France; APHM, Hôpital Sainte-Marguerite, Institute for Locomotion, 13009, Marseille, France. Electronic address: emmanuelle.lefevre@univ-amu.fr.
authors.forename: Emmanuelle
authors.initials: E
authors.lastname: Lefèvre
authors.affiliation: Laboratory of Mechanics and Acoustics, UPR CNRS 7051, Aix-Marseille University, Centrale Marseille, 13009 Marseille, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Lasaygues
authors.affiliation: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France.
authors.forename: Cécile
authors.initials: C
authors.lastname: Baron
authors.affiliation: Laboratory of Mechanics and Acoustics, UPR CNRS 7051, Aix-Marseille University, Centrale Marseille, 13009 Marseille, France.
authors.forename: Cédric
authors.initials: C
authors.lastname: Payan
authors.affiliation: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France; APHM, La Timone, Service de pédiatrie orthopédique, 13385 Marseille cedex 5, France.
authors.forename: Franck
authors.initials: F
authors.lastname: Launay
authors.affiliation: INSERM, UMR 1033, University of Lyon, 69372 Lyon cedex 08, France.
authors.forename: Hélène
authors.initials: H
authors.lastname: Follet
authors.affiliation: Aix-Marseille Université, CNRS, ISM UMR 7287, 13288 Marseille cedex 09, France; APHM, Hôpital Sainte-Marguerite, Institute for Locomotion, 13009, Marseille, France.
authors.forename: Martine
authors.initials: M
authors.lastname: Pithioux
mesh_terms: D000293:Adolescent; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D016880:Anisotropy; D001696:Biomechanical Phenomena; D002648:Child; D002675:Child, Preschool; D005260:Female; D005269:Femur / Q000502:physiology; D005360:Fibula / Q000502:physiology; D006801:Humans; D007223:Infant; D008297:Male; D008422:Materials Testing; D055595:Mechanical Phenomena; D008875:Middle Aged; D000069453:Ultrasonic Waves
keywords: Anisotropy; Cortical bone; Pediatrics; Stiffness coefficients; Ultrasonic wave velocities