Electrical stimulation of bone growth with direct current

Electrical stimulation of osteogenesis was studied in rabbit femora in: (A) a transcortical electric field with a cortex-depolarizing or hyperpolarizing orientation derived from an intramedullary electrode and a ring-shaped counter electrode encircling the femoral shaft; and (B) an electric field derived from an electrode located in the medullary canal and the counter electrode in the abdominal wall. Electrodes were made of platinum. A direct current of 20 microA was applied during six weeks. Contralateral femora with dummy electrodes served as controls. Results were analyzed by optical densitometry of roentgenograms and histomorphometry of histologic slides. Under the conditions of these experiments bone growth was not stimulated by applying a cortex-depolarizing electric field. Significant stimulation of bone growth was only observed at an intramedullary cathode, when the anode was placed at a distance.