Exploring radiogrammetry beyond the second metacarpal: Using the third, fourth, and fifth metacarpals to quantify cortical bone.

Abstract

Traditional metacarpal radiogrammetry, a method for quantifying cortical bone in metacarpals to identify bone loss, typically relies on the presence of an unaltered or undamaged second metacarpal. This study compares the cortical indices of the second to the third, fourth, and fifth metacarpals to test if an additional metacarpal can be used as substitute when the second metacarpal is not available for study. Hand and wrist radiographs from the Burlington Growth Study, belonging to 56 individuals (28 females; 28 males) between 18 and 20 years old, were included in this study. Cortical indices were calculated for metacarpals two through five. Cortical index differences were statistically compared by sex, and the second metacarpal cortical indices were correlated with those of the third, fourth, and fifth metacarpals. The third, fourth, and fifth metacarpal cortical indices were all significantly correlated with the second metacarpal cortical indices for both females and males (p <.05). Cortical indices of the second metacarpal were most strongly correlated with those of the third metacarpal (females r =.644, p <.001; males r=.643, p < .001). The results of this study indicate that the third, fourth, or fifth metacarpal may serve as substitutes for cortical index analyses when the second metacarpal is unavailable or unsuitable for analysis. While the second metacarpal should remain the primary choice in radiogrammetry analyses, the third metacarpal is the most suitable alternative for quantitative analyses of cortical bone.