INVIVO MEASUREMENTS OF ELECTRIC POTENTIAL S IN THE ILISAROW EXTERNAL FIXATOR

Ilisarow's idea that electrical phenomena could contribute to the effi cacy of the ring fixation apparatus prompted us to carry out this prel iminary investigation. Patients with lower leg fractures and a four-ri ng fixation apparatus were selected; the electrical potentials were me asured over non-fractured and fractured bones. Patients who could not be studied in the Faraday box were subjected to great disturbances, ca used by mains voltage and a neighbouring transmitter; in these cases n o objective results could be obtained. Only measurements in the Farada y box yielded reproducible results. The results demonstrate that there is generally a difference in electrical potential among the four ring s in patients fitted with an Ilisarow apparatus. Furthermore, weight-b earing on the fixator-bone system causes changes in the electrical pot ential among the rings.