An Exogen Machine

This sounds like a serious device doesn't it?

The Exogen is simply an ultrasound generator with some fancy electronics to control its use. For example, it is set for a 20 minute period of use only. It can tell whether or not it is attached to a body, and if not, it switches off. It counts how many uses it has had, so that the transducer can be replaced when its life is ended.

There's a velcro band which is strapped around the broken limb, and the transducer fits into a pocket in the strap. The transducer face is lubricated with a coupling gel so that the ultrasound waves are carried into the body.

The theory is that the ultrasound encourages the growth of capillaries in the area of the fracture, and so results in a greater supply of blood to the site of healing.  Apparently it's possible to get a 20% improvement in healing time.  The device is very expensive, and is intended for one user only. The doctors will generally offer the device to people with fractures they fear may not join, or may join slowly.