the best duration of low intensity pulsed ultrasound for accelerating fractured-radial bone repair

we have already shown that low intensity pulsed ultrasonic treatment increases rabbit radial fracture healing. the present experiment was undertaken to find out the best duration for treatment. a complete transverse fracture was made in the right radial bones of21 adult male rabbits by a stanley knife. the animals were divided into 4 groups: group 1, control groups 2, 3, and 4, experimental groups, which received ultrasound (0.5 w /cm2, 1mhz, 2 msec on-8 msec off) for durations of 5,10, and 15 min/day, respectively, from the day after surgery until complete fusion was observed. radiological studies indicated that mean duration of healing was longer and rate of healing was lower in the control compared with those of the experimental groups (p<0.05). however, group 3 showed the least mean healing duration and group 2 and 3 showed the highest healing rate. our results revealed no deleterious effects of ultrasound on treated and untreated ipsilateral and contralateral bones during the experiment or one month after complete fusion of the bones, at which time ultrasound treatment was terminated.