[Acoustic emission analysis of human bones within the scope of clinical diagnosis]

Fractures occurring in human bones produce an acoustic signal, analysis of which permits an evaluation of its source. In the industrial setting acoustic emission analysis (AEA) is used to non-invasively monitor the function of stressed technical systems or parts of systems. During servicing and monitoring of technical systems, acoustic signals emitted by cracks or material deformation are located with the aid of a few acoustic sensors and evaluated for risk-identification purposes. With appropriate technology, therefore, both cortical and trabecular bone can be monitored by acoustic emission analysis. A search is currently ongoing for suitable acoustic technology capable of assessing the extent and location of bone defects and predicting associated risks of fractures occurring. In the present study a system for the measurement and analysis of acoustic emission is described which permits the measurement and analysis of acoustic signals obtained from processed and fresh human and porcine femora. In slightly modified form this system was then used to assess the type and extent of acoustic emission obtained from explanted human femora exposed to cyclical torsional loading until fracture occurred.