title: Bilateral symmetry of biomechanical properties in mouse femora.
abstract: Bone healing and remodeling are commonly examined in animal models by comparing one femur (experimental) to the contralateral femur (control) with the assumption that they are identical with respect to their biomechanical properties. While past studies have characterized the symmetry in geometrical properties in many types of animal bones, few studies have compared the symmetry in the biomechanical properties. The purpose of this study was to determine whether there is symmetry in the mechanical properties of mouse femora. Strain gauges were attached to the posterior surface of the femora of C57BL/6 mice, parallel to the long axis of the bone. The femora were mechanically tested in cantilever bending while strain values were recorded. Moments of inertia, cortical areas, and moduli of elasticity were determined from strains and cross-sectional properties. Mouse femora demonstrated an average strain difference of 0.4% in tension and 1.4% in compression. Elastic moduli differed by 6.6% and 0.9% in tension and compression, respectively, and failure strength differed by an average of 2.0%. Statistical analysis showed there were no significant differences in strain, modulus, or failure load values for the mice, indicating mechanical and geometrical symmetry of mouse femora in cantilever bending.
authors.affiliation: Orthopaedic Research Lab, Department of Orthopaedic Surgery, Arizona Health Sciences Centre, University of Arizona, Room 8352, P.O. Box 245194, Tucson, AZ 85724-5064, USA.
authors.forename: David S
authors.initials: DS
authors.lastname: Margolis
authors.forename: Yeong-Hau H
authors.initials: YH
authors.lastname: Lien
authors.forename: Li-Wen
authors.initials: LW
authors.lastname: Lai
authors.forename: John A
authors.initials: JA
authors.lastname: Szivek
mesh_terms: D019412:Anatomy, Cross-Sectional / Q000379:methods; D000818:Animals; D019245:Compressive Strength / Q000502:physiology*; D004548:Elasticity; D005269:Femur / Q000033:anatomy & histology* / Q000502:physiology*; D066298:In Vitro Techniques; D051379:Mice; D008810:Mice, Inbred C57BL; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013718:Tensile Strength / Q000502:physiology*