Histomorphometric Analysis of Newly-formed Bone Using Octacalcium Phosphate and Bone Matrix Gelatin in Rat Tibial Defects

Background: Repair of bone defects is challenging for reconstructive and orthopedic surgeons. In this study, we aimed to histomorphometrically assess new bone formation in tibial bone defects filled with octacalcium phosphate (OCP), bone matrix gelatin (BMG), and a combination of both. Methods: A total of 96 male Sprague Dawley rats aged 6-8 weeks weighing 120-150 g were randomly allocated into three experimental (OCP, BMG, and OCP/BMG) and one control group (n=24 in each group). The defects in experimental groups were filled with OCP (6 mg), BMG (6 mg), or a combination of OCP and BMG (6 mg, 2:1 ratio). No material was used to fill the defects in the control group and the defect was only covered with Surgicel. Samples were taken on days 7, 14, 21, and 56 after the surgery. The sections were stained with hematoxylin-eosin (H&E) and assessed using light microscopy. Results: In our experimental groups, bone formation was started from the margins of the defect towards the center with an increasing rate during the study period. Moreover, the formed bone was more mature. Bone formation in our control group was only limited to the margins of the defect. The newly formed bone mass was significantly higher in the experimental groups (P=0.001). Conclusion: OCP, BMG, and OCP/BMG compound enhanced osteoinduction in long bones. Level of evidence: III Keywords