A multi-functional portable electro-medical device provides interferential current stimulation to promote bone growth. Two electrical signals are applied to a target area, each electrical signal being formed by a set of two electrode pads. A beat frequency is created at the location the signals intersect with each other. The beat frequency is the difference between the frequencies of the two signals and has an amplitude that is additive and greater than either signal alone. The depth of the interferential signal is increased by increasing the carrier frequency of the signals. The direction of the interferential signal shifts toward the signal having the lower amplitude. The electrical stimulation is used in combination with biologics to further increase bone growth.