Bone mineral density and bone structure parameters as predictors of bone strength: an analysis using computerized microtomography and gastrectomy-induced osteopenia in the rat

In this study the relationships of bone mineral density (BMD) and bone stru cture parameters calculated from 2D microtomography images to bone strength were investigated. Femurs fi-om 21 male Sprague Dawley rats were subjected to dual-energy X-ray absorptiometry, computerized microtomography (C mu T) and either three-point cantilever bending (femoral shaft) or two-point ben ding compression (femoral neck). Gastrectomy was performed on 12 animals an d 9 were sham operated. From the tomograms bone structure analysis was perf ormed using a software routine based on grey level run-length method. Corre lations of BMD and bone structure parameters to mechanical parameters were investigated as were differences between the gastrectomized and the control samples. The reductions of BMD between the groups were 21 and 27% in the f emoral neck and shaft, respectively. For the shaft, the correlations of BMD ro all mechanical parameters were significant and BMD was a consistent pre dictor of bone strength for cortical bone. However, in the femoral neck whe re cancellous bone predominates, BMD was weakly correlated only to deflecti on. A significant correlation between trabecular thickness and neck bone st rength was found. Hence, compared to trabecular thickness, BMD was of limit ed value in predicting bone strength in the femoral neck, (C) 2000 Elsevier Science Ltd. All rights reserved.