It is a two-armed study. The active treatment arm involves participants with acute tibial shaft fractures who have been randomized to receive a PEMF stimulation device to be worn over the fracture site for 10 hours per day during the first twelve weeks after injury. The control arm involves participants with acute tibial shaft fractures who have been randomized to receive a placebo device to be worn over the fracture site for 10 hours per day during the first twelve weeks after injury.