Bone bioelectricity: what have we learned in the past 160 years?

The direct relationship between bone strain and electric fields has spurred continual interest in the field of bioelectricity over the past 160 years. It has been reported that stress-generated potentials alter cell proliferation and extracellular matrix secretion. The observation that endogenous electrical signals facilitate osteoinduction has lead to high production of electrical stimulation devices to fix bone defects. Despite the reported 100,000 nonunions healed as of 1990 with electrical stimulation, skepticism due to lack of homogeneity with trial design and dosage still exists within the scientific community. It is the purpose of this review to assess the bioelectric phenomenon of bone as it applies to piezoelectricity, fracture healing, and overall changes in bone metabolism which occur with controlled electrical stimulation.