1Département d'anthropologie, Université de Montréal, 2Department of Anthropology, Boise State University, 3Anthropology Program, University of Northern British Columbia
Saturday 2:15-2:30, Galleria North
Animal studies have shown that intracortical remodeling is a mechanism that repairs microfractures, which occur naturally in loaded bones. This has been difficult to test in humans because other factors, such as genetics and diet for example, modulate remodeling and are variable among individuals. In order to control for these factors, we compare modeling and remodeling on paired right and left second metacarpals of humans (n=49). We test the hypothesis that the side incurring greater loads will also be characterized by more remodeling. Second moments of area (Imax, Imin, Iap, Iml) and the polar moment of inertia (J) were measured. Osteon population density (OPD) was measured on the anterior, posterior, lateral and medial quadrants. Results for right and left bones are compared with paired t-tests. Relations between macro- and microscopic variables are tested with correlations between percent right-left differences. Right-left comparisons of macroscopic variables (I, J) are all significant, with the right side always being larger on average. However, all right-left comparisons of OPD are not significant. All correlations between the macroscopic variables and combined OPD are significant, but not in the expected direction. Correlations among macroscopic variables and the OPD of specific quadrants are significant only for the medial quadrant. Macroscopic values show that the metacarpals from the right hand incurred greater loads during growth, but, against expectations, there was less remodeling on that side. These results suggest that modeling-remodeling tradeoff mechanisms may be at play and caution is advised when using remodeling as an indicator of loading history.
Funding was provided by NSERC and UNBC seed grant to Lazenby and by FQRSC to Drapeau.