title: Using digital image correlation to determine bone surface strains during loading and after adaptation of the mouse tibia.
abstract: Previous models of cortical bone adaptation, in which loading is imposed on the bone, have estimated the strains in the tissue using strain gauges, analytical beam theory, or finite element analysis. We used digital image correlation (DIC), tracing a speckle pattern on the surface of the bone during loading, to determine surface strains in a murine tibia during compressive loading through the knee joint. We examined whether these surface strains in the mouse tibia are modified following two weeks of load-induced adaptation by comparison with contralateral controls. Results indicated non-uniform strain patterns with isolated areas of high strain (0.5%), particularly on the medial side. Strain measurements were reproducible (standard deviation of the error 0.03%), similar between specimens, and in agreement with strain gauge measurements (between 0.1 and 0.2% strain). After structural adaptation, strains were more uniform across the tibial surface, particularly on the medial side where peak strains were reduced from 0.5% to 0.3%. Because DIC determines local strains over the entire surface, it will provide a better understanding of how strain stimulus influences the bone response during adaptation.
authors.affiliation: Department of Aeronautics, Imperial College, London SW7 2AZ, United Kingdom.
authors.forename: Pavel
authors.initials: P
authors.lastname: Sztefek
authors.forename: Maximilien
authors.initials: M
authors.lastname: Vanleene
authors.forename: Robin
authors.initials: R
authors.lastname: Olsson
authors.forename: Rebecca
authors.initials: R
authors.lastname: Collinson
authors.forename: Andrew A
authors.initials: AA
authors.lastname: Pitsillides
authors.forename: Sandra
authors.initials: S
authors.lastname: Shefelbine
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D003198:Computer Simulation; D055119:Elastic Modulus / Q000502:physiology; D054459:Elasticity Imaging Techniques / Q000379:methods*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008954:Models, Biological; D012815:Signal Processing, Computer-Assisted; D013223:Statistics as Topic; D013314:Stress, Mechanical; D013977:Tibia / Q000033:anatomy & histology* / Q000502:physiology*