Several years ago, low-intensity pulsed ultrasound (frequency 1.5 MHz; sign
al burst width 200 mu s; signal repetition frequency 1 KHz; intensity 30 mW
/cm(2)) was shown to accelerate fresh fracture healing both clinically and
experimentally. On the basis of a prescription use registry, this paper rep
orts on the use of low-intensity pulsed ultrasound in the therapy of 951 de
layed unions and 366 nonunions. The overall success rate for delayed unions
was 91% (average healing time 129 +/- 2.7 days) and for nonunions 86% (ave
rage healing time 152 +/- 5.3 days). Stratifying the data, it becomes clear
that patient medication with calcium channel blockers, nonsteroidal anti-i
nflammatory drugs, and steroids is a negative predictor for healing nonunio
ns, as well as renal or vascular insufficiency. Patients who were smokers d
uring ultrasound therapy had lower healing rates than those who never smoke
d. When comparing the patients of our own clinic treated with low-intensity
ultrasound under study conditions which demonstrate that if healing was ac
hieved it was an effect of the ultrasound therapy to the worldwide prescrip
tion use registry, no difference was seen in healing rate, healing time, or
fracture age. Therefore, the results of these two populations support each
other. Low-intensity pulsed ultrasound may provide a method of nonoperativ
e treatment of great promise for healing disorders. Determination of rankin
g of this new method should be done within the near future.