HR-pQCT based FE analysis of the most distal radius section provides an improved prediction of Colles' fracture load in vitro.

The remarkable performances of high-resolution peripheral quantitative computed tomography (HR-pQCT) make the distal radius a favorable site for early diagnosis of osteoporosis and improved Colles' fracture risk assessment. The goal of this study was to investigate if the HR-pQCT-based micro finite element (μFE) method applied on specific sections of the distal radius provides improved predictions of Colles' fracture load in vitro compared to bone mineral content (BMC), bone mineral density (BMD), or histomorphometric indices. HR-pQCT based BMC, BMD, histomorphometric parameters, and μFE models of 9-mm-thick bone sections were used to predict fracture load of 21 distal radii assessed in an experimental model of Colles' fracture reported in a previous study. The analysis was performed on two bone sections: a standard one recommended by the HR-pQCT manufacturer and a second one defined just proximal to the distal subchondral plate. For most of the investigated parameters, significant differences were found between the values of the two sections. Correlations with experimental fracture load and strength were higher in the most distal section, and the difference was statistically significant for μFE strength. Furthermore, the most distal section was computed to have significantly lower ultimate force and strength by 13% and 35%, respectively, than the standard section. BMC provided a better estimation of Colles' fracture load (R(2)=0.942) than aBMD or any other histomorphometric indices. The best prediction was achieved with μFE analyses of the most distal slice (R(2)=0.962), which provided quantitatively correct ultimate forces.