Bone stimulators work by employing either pulsed electromagnetic energy or pulsed low-intensity ultrasonic energy, according to Berkley Wellness. The bone stimulator is strapped to the body part, even over a cast or brace, and is set to pulse. The energy cannot be felt by the wearer.
The stimulators that employ pulsed electromagnetic energy are generally used on bones that have not properly healed over time, which can be due to poor blood flow or infection. The pulsed low-intensity ultrasonic energy stimulators are used only for new bone fractures. The Food and Drug Administration has approved the use of both stimulators for the treatment of nonunions, or damaged bones that have not entirely healed over time.
It is unclear how the electromagnetic or ultrasonic energy actually aid in the healing of bones, but lab results show that the stimulators clearly affect a variety of factors involved in bone growth and healing, as reported by Berkley Wellness. Studies on the devices have been small and limited, but overall show a positive affect on the healing process of bones. A 2011 review by the Cochrane Collaboration agrees that the evidence points to a positive benefit, but studies have been too few to determine exactly why. Bone simulators are a non-invasive treatment and have not been reported to have any adverse effects, often used as an adjunct to standard treatments.