Ultrasound can affect bone healing both locally and systemically

Bone formation of fractured fibulae stimulated by ultrasound was evaluated with roentgenography and fluorochromes labelling. The fibulae of male New Zealand rabbits were fractured to create a 3 mm-gap. A pilot study was performed to determine the treatment interval for fracture healing of the fibula. Ultrasonic treatment at 1.0 W/cm2, 1.5 MHz for 15 min/day significantly accelerated bone formation at the fracture site of the un-treated fibula, but suppressed the bone formation of the directly treated fractured fibula. Subsequent treatments with these specificities showed that ultrasonic treatment on the unoperated fibula also significantly accelerated the bone formation of the contralateral fractured fibula. It was suggested that locally applied ultrasound at the intensity of 1.0 W/cm2 was deleterious to the treated fracture or intact fibula, but simultaneously would stimulate bone formation of the contralateral fibula.