64 patients with closed femoral shaft fractures were operated on, treated with a locked intramedullary nail and randomized into two groups to determine the effectiveness of electromagnetic stimulation on bone growth. Patients were either treated with magnetic fields and low frequency signals or they received a placebo. The results suggest that electromagnetic stimulation may promote bone healing; however, the difference between the intervention and the control groups was not significant and further investigations are required before definitive conclusions can be drawn.