Foot Bone in Vivo: Its Center of Mass and Centroid of Shape

This paper studies foot bone geometrical shape and its mass distribution and establishes an assessment method of bone strength. Using spiral CT scanning, with an accuracy of sub-millimeter, we analyze the data of 384 pieces of foot bones in vivo and investigate the relationship between the bone's external shape and internal structure. This analysis is explored on the bases of the bone's center of mass and its centroid of shape. We observe the phenomenon of superposition of center of mass and centroid of shape fairly precisely, indicating a possible appearance of biomechanical organism. We investigate two aspects of the geometrical shape, (i) distance between compact bone's centroid of shape and that of the bone and (ii) the mean radius of the same density bone issue relative to the bone's centroid of shape. These quantities are used to interpret the influence of different physical exercises imposed on bone strength, thereby contributing to an alternate assessment technique to bone strength.Comment: 9 pages, 4 figure

Measurement and significance of three-dimensional architecture to the mechanical integrity of trabecular bone

The mechanical properties of trabecular bone have been shown to vary significantly with age, anatomic location, and metabolic condition. Efforts towards predicting its behavior have been extensive, and significant relationship between measures of density and mechanical integrity have been reported. Unfortunately, the significant heterogeneity in trabecular bone anisotropy contributes to significant unexplained variance in its strength and modulus when predicted using scalar measures of mass or density. As a result, numerous investigators have attempted to include measures of architecture in an effort to more rigorously investigate potential physiologic optimization strategies, as well as account for the increased fragility associated with advancing age. In our laboratories we have utilized a unique three-dimensional, microcomputed tomography system to measure trabecular plate thickness, trabecular plate separation, trabecular plate number, surface to volume ratio, bone volume fraction, anisotropy, and connectivity in isolated specimens of trabecular bone. The results of these studies demonstrate that in normal bone, more than 80% of the variance in its mechanical behavior can be explained by measures of density and orientation. The independent measures of connectivity and trabecular plate number were found to be significantly correlated with bone volume fraction, suggesting a potential strategy in the formation of trabecular bone. It might be hypothesized, however, that the relationship between bone volume fraction and connectivity may be substantially altered under conditions associated with aging, fragility, or metabolic bone disease. This hypothesis would be consistent with the histologic, evidence of reduced connectivity in osteopenic patients.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/48005/1/223_2005_Article_BF01673421.pd

Case Report of Spontaneous, Nonspinal Fractures in a Multiple Myeloma Patient on Long-term Pamidronate and Zoledronic Acid

Pamidronate and zoledronic acid are two potent intravenous bisphosphonates used in the treatment of multiple myeloma as well as osteoporosis. While the concern for heightened fracture risk in a patient on long-term bisphosphonate treatment for malignancy has been previously noted, we present the first case of spontaneous, nonspinal fractures in a patient undergoing treatment for multiple myeloma. The patient had a positive 9-year history of bisphosphonate treatment and presented with sequential subtrochanteric stress fractures of the left and right femurs. Pathological reports of fracture site biopsies demonstrate signs consistent with ametabolic bone and no malignancy. These findings point to extreme inhibition of bone turnover by bisphosphonates as the cause of this patient’s morbidity. This is a single retrospective case study (level IV evidence)