In vivo detection of structural differences between dominant and nondominant radii using peripheral quantitative computed tomography

This cross-sectional study identifies differences in distal radial trabecul ar bone structure related to habitual loading patterns in the upper extremi ties using high-resolution peripheral quantitative computed tomography. As well, it determines whether measurements of these indices in one limb serve as satisfactory surrogates for the contralateral limb. The dominant and no ndominant forearms of 106 adult volunteers (mean age [standard deviation], 44.3 [17.5] yr) were scanned, and indices of trabecular bone structure (con nectivity index maximum hole size [H-M] and mean hole size [H-A]) were dete rmined at the distal radius. The images were also analyzed to determine bon e density. For all subjects, H-M was significantly smaller in the dominant radius (p < 0.01). Right-handed subjects (n = 96) had a greater connectivit y index (p < 0.05) and smaller H-M (p < 0.01) in the dominant radius. For t he total group, the dominant limb had a greater mass (total and cortical bo ne mineral content, p < 0.01 and p < 0.05, respectively) and greater total bone volumetric density (p < 0.05). There were no significant differences b etween limbs for the group of left-handed subjects (n = 10). As expected, s ignificant associations exist between side-to-side measurements of bone str ucture and density (p < 0.001). The correlation coefficients for connectivi ty index, H-M, and H-A were 0.86, 0.85, and 0.87, respectively. For bone de nsity, the between-limb associations were 0.90, 0.73, and 0.92 for the tota l, cortical, and trabecular bone compartments at the distal radius. Differe nces in the structure of the trabecular bone network suggest that different ial loading of the dominant limb preserves bone strength.