ELECTRICAL EFFECTS IN BONE

This paper presents a review of the work carried out on the electromechanical properties of bone over the past three decades. Research in this field has established the piezoelectric nature of bone and identified collagen as the generating source in dry bone. Some of the characteristics of the strain generated potential (SGP) signal from dry and hydrated bone were found to be unaccountable in terms of a classical piezoelectric theory. Modifications of the theory were suggested, and in the case of fully hydrated bone, a new mechanism (streaming potential) has emerged. The paper also reports on recent developments in the field and presents results from microstructural (osteonic) studies and from fluid-filled bone. The review indicates the need for actual in vivo work, because most of the reported data were obtained, in the last decade, from in vitro work and were considered valid in vivo. Modeling of the mechanism which produces the SGP has been considered to explain the characteristics of these potentials. A representative model recently developed by the present authors and co-workers is reported.