Electromagnetic Therapy. Areas of active bone growth and regeneration or areas of bone deposition during physiologic bone remodeling are electronegative with respect to less active areas; thus, electric fields may be part of the normal process of bone development and regeneration.
Direct electrical currents have been used to treat nonunion fractures and osteotomies, as first described in 1971, which are reported to respond well to applications of either cathodal current or electromagnetic fields.
Bone regeneration can be accelerated in osteotomies made 3.5–4.5 cm distal to the head of the fibula in dogs. A voltage field was induced in the fibula by inductively coupling pulsed electromagnetic fields of low frequency and strength directly to the bone across the skin. Not only did the stimulated osteotomies heal faster than control osteotomies but also the regenerated bone was more highly organized and stronger than control regenerated bone, even though the mass of callus formed was less than in controls. This method has been used to successfully treat tibial pseudoarthroses in young patients. Pseudoarthrosis is a rare, local bone dysplasia that has a very low probability of correction by conventional techniques. Pulsed electromagnetic fields have also been used as a noninvasive postoperative treatment for lumbar vertebral fusion.
The use of electromagnetic fields has been advocated to promote the synthesis of extracellular matrix proteins of bone cells and the secretion of growth factors from osteoblasts to stimulate angiogenesis and new bone formation. Pulsed electromagnetic field therapy may enhance angiopoietin-2 expression. It may also affect several membrane receptors and stimulate osteoblasts to secrete several growth factors such as BMPs 2 and 4, TGF-β, and FGF2. These anabolic effects of electromagnetic fields on bone formation contribute to the enhancement of fracture repair.
J. Li, D. Stocum (2019). Chapter 12 – Fracture Healing: Effects of Mechanical and Electrical Stimulation on Fracture Repair. Basic and Applied Bone Biology (Second Edition) 2019, Pages 235-253