Biomechanics of Bone

Abstract

The ability to bear loads is a critical function of the skeleton, in addition to its metabolic and physiological roles. Load-bearing ability depends on both the applied loads and the structural properties of the loaded bone. When the loads exceed the structural properties, fracture will occur. Because the nature of the applied loads can be difficult to predict, the best approach for minimizing fracture risk is through targeted interventions and therapies to improve bone strength. The strength and fracture resistance of the skeleton depend primarily on the quantity, geometry/architecture, and material properties of bone tissue. Although each of these attributes has been examined independently in both cortical and cancellous bone, no single measurement can fully characterize the structural integrity of bone or reliably predict the occurrence of a fracture in individuals. In addition, factors such as aging, trauma, and disease affect the tissue properties and can compromise bone strength. While bone quantity and, more recently, architecture have been widely examined in vivo, these measures do not fully explain variations in bone mechanical properties observed experimentally ex vivo. Healthy bone tissue exhibits spatial and temporal variations in tissue-level material properties that are altered by aging and disease. Accurately characterizing bone material properties, whether at the tissue level or at the chemical composition level of the mineral and matrix constituents, may improve the ability to predict structural competence and fracture risk reliably for individuals.