Electrical stimulation: Nonunions

The current paper attempts to provide an overview on the currently available fundamental, preclinical, and clinical evidence on the biologic rationale and therapeutic efficacy of electrical stimulation devices applied in patients with long-bone nonunions. Electrical stimulation (ES) involves the generation of an electrical or electromagnetic current through the ununited fracture. Such currents, which are present in physiologically healing bone, provide stimuli that favor a healing response to bone cells. These stimuli include the enhancement of transmembrane and intracellular calcium-mediated signal transduction and an increased synthesis of paracrine and autocrine growth factors by osteoblasts. Favorable healing union rates, ranging from 43% to 90%, as found by several clinical case series, have prompted the orthopedic community to, at least partially, adopt ES for the treatment of long bone nonunions. Nonetheless, randomized controlled trials have not provided definitive evidence of ES causing nonunions to heal more often than sham devices. This impediment is probably formed by small sample sizes, lack of consistency regarding the definition of union and nonunion, and variability in ES current used.