Electrical callus and callus formation by electret.

The callus formed by passing an electric current through bone is called electrodynamic callus. The amount of electrical current determines the quality of the callus (osseous, cartilagenous, or fibrous). Callus forms first at the negative pole and grows toward the positive pole. The callus formed by placing a teflon film electret near the surface of bone is called electrostatic callus. The amount of this callus is larger when the bone is wrapped by the electret film than when the film is laid over the bone.