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Journal ArticleDOI

Mechanical and morphological aspects of experimental overload and fatigue in bone.

01 May 1970-Journal of Biomechanics (Elsevier)-Vol. 3, Iss: 3, pp 263-270
TL;DR: The author reports the results of experiments in which long bone fatigue is produced in 30 pairs of dog ulnas by applying opposing forces at both extremities thereby causing a strain.
About: This article is published in Journal of Biomechanics.The article was published on 1970-05-01. It has received 155 citations till now.
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2,428 citations

Journal ArticleDOI
TL;DR: Data from two experiments support the hypothesis that fatigue microdamage is a significant factor in the initiation of intracortical bone remodeling.

759 citations

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TL;DR: The results of this study would suggest that adaptive bone remodeling is extremely sensitive to alterations in both the magnitude and distribution of the strain generated within the bone tissue.

508 citations

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TL;DR: Three complementary in vivo experiments using dog ulnas demonstrated that adaptive hypertrophy of long bones is provoked only by intermittent compressions and not by static compression.

445 citations

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TL;DR: In patients with suspected stress injury, radiographs should be obtained a second time, 1-2 weeks after the initial study, and biopsy should be avoided until evidence is clear-cut that the lesion has not changed over a short time.
Abstract: Stress fractures are extremely common lesions that occur in specific areas and are related to specific activities. They are caused by increased muscular activity on bones that are not yet ready to take the increased pull of the involved muscles. The insufficiency type of stress fractures found in patients with bone of diminished mineral content is being recognized more often as increasing numbers of middle-aged and elderly persons are becoming more physically active. A variety of imaging studies can be used to diagnose stress fractures. Radionuclide bone scanning and MR imaging often show abnormalities early in the course of the injury. However, when radiographs appear normal, findings on scintigrams may be more suggestive of the proper diagnosis. In patients with suspected stress injury, radiographs should be obtained a second time, 1-2 weeks after the initial study. Biopsy should be avoided until evidence is clear-cut that the lesion has not changed over a short time.

376 citations

References
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TL;DR: The comparison of compressive properties in single osteons and in macroscopic bone samples seems to support the view that the osteon is actually the mechanical unit of compact bone.
Abstract: The compressive strength of single human osteons has been investigated in specially prepared samples using a microtesting machine equipped with a microwave micrometer. The main conclusions which can be drawn from our results are: (1) In agreement with Gebhardt's theories the ultimate compressive strength is greatest for osteons having transversally oriented fiber bundles, lowest for osteons having longitudinally oriented fiber bundles, and intermediate for osteons whose fiber bundles change direction in successive lamellae through an angle of about 90°. (2) The modulus of elasticity is greatest in osteons with transversally oriented fiber bundles. (3) With all three types of osteon the stress-strain curves for fully calcified osteons are markedly different from those for osteons with low calcium content, the modulus of elasticity being much lower in osteons of the latter type. (4) Age seems to have no measurable influence on the compressive properties of osteons. (5) The comparison of compressive properties in single osteons and in macroscopic bone samples seems to support the view that the osteon is actually the mechanical unit of compact bone. (6) Fracture in osteon samples starts with microscopic fissures induced by shearing. (7) In every case these fissures form an angle of roughly 30°–35° with the axis of the osteon and do not appear to vary with the microscopic osteon structures. (8) Electron microscopy reveals distortion of bone crystals and breaking of collagen fibrils at the edges of the fissures.

371 citations

Journal ArticleDOI
TL;DR: The tensile stress‐strain curves show that, even at the level of single osteons, bone behaves like a complex material, which, according to Sedlin, can be represented by a Hooke body linked in series to a Kelvin body.
Abstract: The ultimate tensile strength and modulus of elasticity of individual osteons from human and ox compact bone were determined with a specially designed microwave extensimeter. The results were related to the degree of calcification and the orientation of collagen fiber-bundles in successive lamellae of the osteons. The following conclusions were made: (1) When osteon specimens are dried, their tensile strength and modulus of elasticity increase, while their percent elongation under tension falls. (2) In the osteon samples tested wet, the degree of calcification induces an increase in the modulus of elasticity with additional amounts of calcium salts. (3) The modulus of elasticity in tension of the organic matrix corresponds to that of collagen. (4) In the osteons having a marked longitudinal arrangement of bundles of fibers in successive lamellae, the ultimate tensile strength and modulus of elasticity seem greater and the percentage elongation under tension seems lower than in osteons whose bundles in successive lamellae change through an angle of about 90°. (5) The tensile properties of osteons seem independent of the age of the subject. (6) Human and ox osteons reveal the same tensile behavior. (7) The tensile stress-strain curves show that, even at the level of single osteons, bone behaves like a complex material, which, according to Sedlin, can be represented by a Hooke body linked in series to a Kelvin body.

327 citations