Microarchitecture parameters describe bone structure and its strength better than BMD.

INTRODUCTION AND HYPOTHESIS

Some papers have shown that bone mineral density (BMD) may not be accurate in predicting fracture risk. Recently microarchitecture parameters have been reported to give information on bone characteristics. The aim of this study was to find out if the values of volume, fractal dimension, and bone mineral density are correlated with bone strength.

METHODS

Forty-two human bone samples harvested during total hip replacement surgery were cut to cylindrical samples. The geometrical mesh of layers of bone mass obtained from microCT investigation and the volumes of each layer and fractal dimension were calculated. The finite element method was applied to calculate the compression force F causing ε = 0.8% strain.

RESULTS

There were stronger correlations for microarchitecture parameters with strength than those for bone mineral density. The values of determination coefficient R(2) for mean volume and force were 0.88 and 0.90 for mean fractal dimension and force, while for BMD and force the value was 0.53. The samples with bigger mean bone volume of layers and bigger mean fractal dimension of layers (more complex structure) presented higher strength.

CONCLUSION

The volumetric and fractal dimension parameters better describe bone structure and strength than BMD.