A Cochrane review included 4 studies with a total of 125 subjects. Three studies evaluated the effects of pulsed electromagnetic fields and one study, capacitive coupled electric fields. Most data related to non-union of the tibia. The primary measure of the clinical effectiveness was the proportion of participants whose fractures had united at a fixed time point. The overall pooled effect size was small and not statistically significant (risk ratio 1.96; 95% CI 0.86 to 4.48; 4 trials). There was substantial clinical and statistical heterogeneity in the pooled analysis (I2 = 58%).
Comment: The quality of evidence is downgraded by limitations in study quality (inadequate follow up, poor reporting), by indirectness (changes in the practices concerning prevention and treatment of non-union), by inconsistency (variability in results across studies), and by imprecise results (limited study size for each comparison).