Surprising Effect - ultrasound used to heal bone fractures

Why ultrasound does this is not understood - but it has been shown that the effect is real - and it is being marketed.

There is good scientific evidence showing that certain fractures, specifically nonunions, can show faster healing with the use of ultrasound. There is also evidence that these devices can help in patients who have poor healing potential including diabetics, smokers, and patients taking oral steroid medications.

It is not known which effect of ultrasound on cells alters the healing process but ultrasound has several effects that may alter the rate at which fractures unite. It has been shown that ultrasound causes effects ranging from small temperature changes is the tissue to increased gene expression.