Ultrasound influence on internal fixation with a rigid plate in dogs

The effect of ultrasound on the fixation of 3-hole AO plates on the femur and humerus in dogs was investigated. Four weeks postoperatively the screws were loosened by a torque (kg/cm) that averaged one-third of the inserted torque. The removal torque of screws exposed to ultrasound tended to be lower than that of unexposed screws, but the difference was not statistically significant. Thus therapy with ultrasound in clinical dosages may be used without influence on the fixation of a rigid plate.