Platelet-rich plasma on calcium phosphate granules promotes metaphyseal bone healing in mini-pigs.

The role of platelet-rich plasma (PRP) as a promoter of bone healing remains controversial. The aim of this study was to investigate the effect of PRP in combination with calcium phosphate granules (CPG) on bone defect healing in a metaphyseal long bone defect. A metaphyseal bone defect at the proximal tibia of 16 mini-pigs was filled with CPG combined with autologous PRP or CPG solely (control group). The PRP showed 4.4-fold more platelets compared to peripheral blood. Six weeks after surgery the radiological and histomorphometrical evaluations showed significantly more bone formation in the PRP group in the central area of the defect zone (p < 0.01) as well as the cortical defect zone (p < 0.04). Furthermore, the resorption rate of CPG was increased in animals who received PRP. Nevertheless there were only isolated instances of complete osseous bridging of the bone defects even in the PRP group. This study demonstrates that a PRP-CPG composit promotes bone regeneration but does not lead to a solid fusion of a tibial defect in mini-pigs.