Bone microarchitecture evaluated by histomorphometry
ABSTRACT The increasing use of densitometric devices for assessing bone fragility has progressively strengthened the assumption that mass is the most important property determining bone mechanical competence. Nevertheless, structure and microarchitecture are relevant aspects of bone strength. The study of microarchitecture is based on the measure of width, number, and separation of trabeculae as well as on their spatial organization. There are several methods to assess bone architecture, particularly at the trabecular level. In particular, histomorphometry, based on the use of optical microscopy and on the principles of quantitative histology and stereology, evaluates microarchitecture two-dimensionally, even if these measures appear well correlated to the three-dimensional structure and properties of bone. In addition, new computerized methods allow the acquisition of more sophisticated measurements by means of a digitizer have been introduced to integrate the use of the microscope. These methods supply information on trabecular width as well as on its distribution and on the organization of the trabeculae in the marrow space.Microarchitecture seems to be a determinant of bone fragility independent of bone density and it is important for understanding the mechanisms of bone fragility as well as the action of the drugs used to prevent osteoporotic fractures. Several in vivo studies (on animals and humans) can provide an additional interpretation for the anti-fracture effect of such drugs. For instance, bisphosphonates and parathyroid hormone seem to preserve or even improve microarchitecture. The challenge for the future will be to evaluate bone quality in vivo with the same or better resolution and accuracy than the invasive methods used today.
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ABSTRACT: There is a potential for the use of pharmacological agents to enhance the quality of bone around a total hip or knee prosthesis, reducing the risk of implant failure or periprosthetic fracture. Bisphosphonates are currently used for the management of postmenopausal osteoporosis and recent investigations also suggest a potential role for the management of postoperative periprosthetic bone loss. Current evidence suggests that the short-term gains may not be sustained in the long term. Teriparatide and parathyroid hormone 1-84 have been licensed to treat postmenopausal osteoporosis and may also be investigated for the potential to enhance periprosthetic bone mass. In addition, other agents such as calcitonin and strontium ranelate, non-anabolic agents such as doxycycline, and recombinant OPG adeno-associated virus (rAAV) gene therapy, may in the future provide solutions for enhancing periprosthetic bone mass.Injury 07/2007; 38(6):704-13. · 1.98 Impact Factor