Gross and histomorphological evaluation of therapeutic ultrasound (0.5 W/cm(2)) following autogenous cancellous bone grafting in dogs

In 8 clinically healthy mongrel dogs divided into 2 groups of 4 animals eac h, a transverse mid shaft diaphyseal defect of 2 cm was created in the righ t radius. The gap was filled up with cancellous bone harvested from proxima l end of the left tibia and fixation was achieved with bone plate in both t he groups. Group 1 served as control and in group 2, the pulsed ultrasound therapy @ 0.5 W/cm(2) was applied for 10 min daily for 10 days. After 60 da ys, the callus from the grafted site was collected and subjected to microsc opic study. These findings indicated that fracture site in the control grou p was in early part of the reparative phase (osteoinduction) of the healing and the bone grafts were in the process of resorption even at the end of o bservation. In ultrasound-treated animals the findings were suggestive of l ate part of the reparative stage of bone healing as the grafted cancellous bone was fully reabsorbed and replaced by the newly formed cancellous bone with active haemopoiesis.