Evaluation of Low Intensity Pulsed Ultrasound Effects on the Osteogenesis Potential of Demineralized Bone Matrix in Experimental Tibial Defect in Rabbits

Background: Many studies have assessed the effects of either low intensity pulsed ultrasound (LIPUS) or demineralized bone matrix (DBM) on bone repair; however, an evaluation of the combination of these modalities (LIPUS + DBM) has not yet been considered. Objectives: This study aimed to investigate combined effects of DBM and LIPUS on fracture healing. Methods: Bilateral 5-mm tibial defects were created in male Dutch rabbits (n = 30). Animals were divided to two groups of empty defect (A) and DBM group (B), in which commercial DBM putty was used in defects. In each animal left tibia was treated with LIPUS (intensity = 30 mW/cm2, I SATA, 1 MHz, 20 min/day, pulsed duty 1:4) and the contralateral limb was used as the control. Animals, after 14, 28 and 60 days, were submitted to radiographic or computerized tomography (CT) scanning analysis. Results: At two weeks, LIPUS had no substantial effect on bone formation. Slight increase of average rates in LIPUS group (A2) were seen compared to the empty defect group (A1) at day 21 and 28. In the DBM–treated group compared with the sham LIPUS, bone-healing rate was reduced at the end of the period (60 days) after surgery. The average healing rate in group B at the end of the 60-day period was less than group A after 21 days. Conclusions: The present study discusses systemic effect of LIPUS because of non-significant results between treated group and control group and is the first to demonstrate that LIPUS decreases bone formation induced by DBM.