Validation of an HR-pQCT-based homogenized finite element approach using mechanical testing of ultra-distal radius sections

Osteoporotic (Colles' type) fractures of the distal radius occur relatively early in lifetime and could estimate risk of fracture of other, more endangered anatomical sites. High-resolution peripheral quantitative computed tomography (HR-pQCT) based micro finite element (μFE) analysis was shown to better predict fracture load of the distal radius than densitometry or histomorphometric measures. As an alternative to μFE, homogenization-based FE (hFE) approach may provide at least equivalent predictive power with reduced computational needs. The aim of this study was to validate the hFE approach with compression tests of 25 distal radius sections extracted at the location which is relevant in Colles' fractures. HR-pQCT-based input parameters of the hFE models were calibrated with respect to μCT. HR-pQCT-based hFE models were then built and their ability to predict experimental stiffness and ultimate load was compared to those of the density-based parameters, histomorphometric indices and μFE models assessed from the same input images. Bone mineral content was the best non-FE-based predictor (R² = 0.86) of ultimate force. Both FE methods were not only the strongest predictors, but provided quantitatively correct fracture loads. The calibrated hFE approach provided closely as strong prediction (R² = 0.94) as μFE (R² = 0.95), but the former was computationally cheaper. The results of this validation study suggest that FE simulation could be used as an efficient and precise tool to predict Colles' fracture load.