Repair of nonunions by electrically pulsed current stimulation.

Five congenital and 52 acquired nonunions of bone were stimulated using an invasive device. The unit delivered a constant but pulsed right-angled current of positive polarity measuring 20 to 25 muAmps (voltage of 750 mV) and a frequency of 20 Hz. The power pack encapsulated in epoxy resin was implanted at the time of operative fragment stabilization. THe cathode was inserted at the site of the nonunion gap. After two to 12 months, all but two of the acquired nonunions and one of the congenital pseudarthroses healed. In the unsuccessful cases, the bone ends were often totally necrotic. Four cases required reimplantation because of broken wires or expiration of the battery, and two cases failed owing to purulent infection. Electrostimulation is an adjuvant treatment to fragment stabilization in hyporeactive and hypovascular or congenital pseudarthroses. Electrical stimuli may be assumed to simulate conditions which are essential for bone healing.