Current applications of electrotherapeutics in collagen healing

Electrical current flow appears to be integral to the healing of collagen containing tissue, i.e., bone, cartilage, ligaments, tendons and skin. Accordingly, it is reasonable to hypothesize that externally applied electrical fields should be able to enhance healing, especially in conditions that have resisted more standard treatments. Nevertheless, applications of electrotherapeutics is challenging because the precise mechanism of action is unknown and, accordingly, there is an almost unlimited combination of stimulation parameters (e.g., type of waveform, voltage, current, phase, frequency, etc.) that can be applied to a treatment site. Presently, of the three major types of electrical stimulation, i.e., direct, and capacitive and inductive coupling, there is a growing trend toward utilization of the latter because of its efficacy and greater margin of safety. Although the mechanisms of action for enhanced healing of all three types remain elusive there is increasing evidence that electrical stimulation exerts its influence via effects at the cellular and/or molecular levels within the tissue. Utilization of electrotherapeutics has been most prevalent in bony injuries resistant to healing, but applications to severe lesions of skin and ligaments, and even to degenerative joint disease seems promising as cartilage has been shown to be more responsive than bone to applied electrical energy. We conclude that there is a clear trend toward greater orthopedic utilization of inductive stimulation and that, despite the lack of definitive guidelines relating specific parameters with specific conditions, electrotherapeutics appears to be a safe and often effective treatment for collagen containing tissues in many cases in which more standard therapies have failed.