Document Type

Article

Publication Date

1-7-2003

Keywords

Adaptation, Physiological, Animals, Cattle, Chelating Agents, Compressive Strength, Elasticity, Fluorescent Dyes, Fractures, Stress, Haversian System, Microscopy, Fluorescence, Stress, Mechanical, Tibia, Weight-Bearing

Comments

This article is available at http://www.sciencedirect.com/science

Abstract

Fatigue damage in bone occurs in the form of microcracks. This microdamage contributes to the formation of stress fractures and acts as a stimulus for bone remodelling. A technique has been developed, which allows microcrack growth to be monitored during the course of a fatigue test by the application of a series of fluorescent chelating agents. Specimens were taken from bovine tibiae and fatigue tested in cyclic compression at a stress range of 80MPa. The specimens were stained before testing with alizarin and up to three other chelating agents were applied during testing to label microcracks formed at different times. Microcracks initiated in interstitial bone in the early part of a specimen's life. Further accumulation of microcracks is then suppressed until the period late in the specimen's life. Microcracks were found to be longer in the longitudinal than in the transverse direction. Only a small proportion of cracks are actively propagating; these are longer than non-propagating cracks. These results support the concept of a microstructural barrier effect existing in bone, whereby cracks initiate easily but slow down or stop at barriers such as cement lines.

Disciplines

Anatomy

Citation

O'Brien FJ, Taylor D, Lee TC. Microcrack accumulation at different intervals during fatigue testing of compact bone. Journal of Biomechanics 2003;36(7):973-80

PubMed ID

12757806

DOI Link

10.1016/S0021-9290(03)00066-6


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