The purpose of this study was to determine whether low-power-consuming
symmetrical-waveform electromagnetic stimuli could increase the stiffness
of fracture sites in a rabbit fibular-osteotomy model. Both active and
placebo devices were used in a blinded study protocol. Dose-response
studies of pulse amplitude and pulse width were performed by continuous
application (twenty-four hours a day) of repetitive (fifteen-hertz),
bursted (five-millisecond-long) symmetrical, rectangular electromagnetic
stimulus waveforms. The power consumed by these stimuli is approximately
one-fifth that consumed by the pulsing electromagnetic field devices that
are in current clinical use. Significant increase of callus bending
stiffness was produced by pulse widths of five to seven microseconds and
pulse amplitudes of fifty to 100 millivolts.