Assessment of bone mineral content byin vivo measurement of flexural wave velocities

The determination of loss of bone mineral in an early stage of development is important. At the present time there exists no noninvasive or nonradiological methods which can be used for routine checks. An alternative method to obtain information about mineral content of bone is to measure the mechanical properties. A new method to measure the mechanical properties of long bones by means of the dispersion analysis of flexural waves is proposed. To be independent of the frequency spectrum of the impact pulse, the phase velocities were calculated from the signals of two accelerometers placed in vivo on the tibia. This method has the advantage that the velocities can be calculated for a frequency range. The results from this method were compared with the results from a well established measurement method for bone mineral content. Both methods were applied to 43 subjects selected in such a way that a broad range of bone mineral values was covered. The results imply that the proposed method can be used to test the mechanical properties of long bones.