Low-intensity pulsed ultrasound promotes the osteogenic effect induced by bone allograft

Objectives: The aim of this study was to investigate the combined effects of bone allograft and lowintensity pulsed ultrasound (LIPUS) on osteogenesis using a bone allograft model. Methods: Femora and tibiae were harvested from 8 Wistar rats. These long bones were used for bone allografts. Subsequently, two groups were studied. In the bone allograft group, freeze-dried bone was fixed unilaterally to the anterior surface of the femur in 42 Wistar rats. In the sham-operation group, the same procedure was performed but without a bone allograft in 8 rats. The right femora were exposed to LIPUS for 20 minutes per day, beginning the day after surgery and continued until harvest in both groups. X-ray, three-dimensional micro-computed tomography (3D micro-CT) and histological analysis were performed. Results: In the bone allograft group, x-ray, 3D micro-CT, and histology showed that LIPUS promoted intramembranous ossification induced by the bone allograft, and suggested that LIPUS accelerated the differentiation of mesenchymal stem cells in the cambium layer. Conclusions: LIPUS facilitates the osteogenic effect induced by a bone allograft. LIPUS has been successfully used to accelerate fracture healing. Therefore, we anticipate that earlier clinical application of LIPUS treatment to bone allograft may represent a promising approach for accelerating bone healing.