Effect of platelet-rich plasma on bone regenerate consolidation in distraction osteogenesis: An experimental study in rabbits

Objective: The aim of this study was to determine the effect of platelet-rich plasma (PRP) on bone regenerate consolidation in a rabbit model of distraction osteogenesis. Methods: In this study, 12 male New Zealand rabbits weighing 1600 to 2000 g were used. All the rabbits were randomly divided into two groups (n = 6 per group): PRP group and control group. A two-ring, circular external fixator was applied to the right tibia of each rabbit in both groups. After corticotomy, all the tibiae were distracted at a rate of 0.5 mm/day for 20 days. PRP was injected to the osteotomy sites on the 7th, 14th, and 21st days postoperatively. Mineral density of the new bone tissue formed in the distraction zone was measured using quantitative computed tomography in the 3rd, 4th, and 5th weeks. At the end of the 6th week, the animals were sacrificed, and the specimens were evaluated biomechanically and histologically. Results: Microcomputed tomography assessment showed significant bone mineral density increase from the 3rd to the 6th week (62.3% and 43.7% for the PRP and control groups, respectively). In the PRP group, the measurements on the 3rd, 4th, and 5th weeks were 416 +/- 29, 487 +/- 9.9, and 675 +/- 37.8HU (Hounsfield units), respectively, whereas in the control group were 313, 374, and 450 HU, respectively. In the comparison of weekly measurements of the two groups, the increase in bone density in the PRP group was higher than that in the control group (P < 0.001). During the mechanical tests, in the PRP group, the mean torsion was 46.50 degrees and the mean torque 0.53 Nm, while in the control group, the mean torsion was 19.33 degrees and the mean torque 0.65 Nm. The mechanical analysis of the groups revealed significant differences in the mean maximum torsion angles (P = 0.024). The histological examination showed that both groups had external and internal periosteal calli. Callus tissue in four rabbits in the PRP group and two rabbits in the control group was remodeled; normal bone formation occurred and distracted bone ends were completely healed. Conclusion: The results of the present study have indicated that PRP injection can enhance bone regenerate consolidation and increase bone mineral density during the healing process of distraction osteogenesis.