Lucas, Matthew W. (2009-08). A Novel Method for the Evaluation of Mechanical Properties of Cancellous Bone in the Rat Distal Femur. Master's Thesis. Thesis uri icon

abstract

  • The mechanical properties of the cancellous bone in the laboratory rat animal model are of great interest to the research community for the evaluation of treatments for osteoporosis. Cancellous bone responds rapidly and dramatically to disuse, various pathologies, nutritional deficiencies, and hormonal deficiencies and hence is often a primary focus in animal studies. Previous methods for evaluating the mechanical properties of cancellous bone in rat test specimens included both cortical and cancellous bone. This thesis introduces a new method to core cancellous specimens using a diamond wire saw in concert with specially designed fixtures. This method has been termed Isolated Cancellous Coring (ICC). The location and the geometry of the cored specimens were determined based on uCT analysis. The isolated cancellous specimens were subjected to uni-axial compression testing to evaluate the mechanical properties. Furthermore, the new method is evaluated by directly applying it to a study investigating the effects of estrogen replacement therapy in post-menopausal osteoporosis as simulated by the ovariectomized rat model. The results show that the ICC method can be applied to bone specimens with a large range in density and micro-architecture parameters. The compression testing of the isolated cancellous specimens provides a sensitive indicator of the effects of osteoporosis and treatment on the mechanical properties of the cancellous bone in the distal rat femur. Also, the results indicate a possible discordant relationship between bone mineral density and bone strength with respect to estrogen treatment. Power law regressions show that approximately 50% of the variation in ultimate strength can be accounted for with bone mineral density and the percent of bone volume per total volume.
  • The mechanical properties of the cancellous bone in the laboratory rat animal
    model are of great interest to the research community for the evaluation of treatments for
    osteoporosis. Cancellous bone responds rapidly and dramatically to disuse, various
    pathologies, nutritional deficiencies, and hormonal deficiencies and hence is often a
    primary focus in animal studies. Previous methods for evaluating the mechanical
    properties of cancellous bone in rat test specimens included both cortical and cancellous
    bone. This thesis introduces a new method to core cancellous specimens using a
    diamond wire saw in concert with specially designed fixtures. This method has been
    termed Isolated Cancellous Coring (ICC). The location and the geometry of the cored
    specimens were determined based on uCT analysis. The isolated cancellous specimens
    were subjected to uni-axial compression testing to evaluate the mechanical properties.
    Furthermore, the new method is evaluated by directly applying it to a study investigating
    the effects of estrogen replacement therapy in post-menopausal osteoporosis as
    simulated by the ovariectomized rat model.
    The results show that the ICC method can be applied to bone specimens with a
    large range in density and micro-architecture parameters. The compression testing of the
    isolated cancellous specimens provides a sensitive indicator of the effects of
    osteoporosis and treatment on the mechanical properties of the cancellous bone in the
    distal rat femur. Also, the results indicate a possible discordant relationship between
    bone mineral density and bone strength with respect to estrogen treatment. Power law regressions show that approximately 50% of the variation in ultimate strength can be
    accounted for with bone mineral density and the percent of bone volume per total
    volume.

publication date

  • August 2009