[The effects of electrical stimulation on epiphyseal cartilage]

The effects of electrical stimulation on epiphyseal growth were studied. The epiphyseal cartilage of the proximal tibia of New Zealand white rabbits was stimulated by direct current for 2 weeks. A constant direct current of 5 microA was supplied by an electrical stimulation system buried under the subcutaneous tissue. Contralateral tibia with dummy electrodes served as control. The results were as follows: The height of the epiphyseal plate near the electrodes was slightly increased by traumatic reaction to the electrodes in the control group. However, in the stimulation group, the height was more remarkably increased than in the control group. The height of the epiphyseal plate was 0.6 +/- 0.2 mm in the control group, and 1.0 +/- 0.4 mm in the stimulation group, showing a statistical difference. The mineral appositional rate, determined by tetracycline labels, was 3.0 +/- 0.8 microns/day in the control group and 4.6 +/- 0.4 microns/day in the stimulation group. It was observed that the turnover of the epiphyseal plate was accelerated in the stimulation group, but no other abnormal findings were observed by electron microscopy. In conclusion, it is clear that growth of the epiphyseal cartilage is accelerated by direct current.