Improvement in angiogenesis and osteogenesis with modified cannulated screws combined with VEGF/PLGA/fibrin glue in femoral neck fractures

Angiogenesis is essential for bone healing. Vascular endothelial growth factor (VEGF) is regarded as one of the most potent antigenic cytokines; however, there have been very few studies that have previously investigated the effects of VEGF on bone healing in a femoral neck fracture model. Thus, the aim of the present study was to test both the angiogenic and osteogenic properties of a VEGF/poly-lactic acid glycolic acid (PLGA) delivery system for the treatment of femoral neck fractures. VEGF/PLGA microspheres were prepared by the double emulsion solvent-evaporation method and in vitro VEGF release was quantified by an ELISA assay. Then the preparation of femoral neck fracture model and internal fixation were performed, and the effect of the VEGF/PLGA microspheres on bone healing was determined by X-ray, radionuclide bone scanning, and histomorphometric evaluation. The release of VEGF from the VEGF/PLGA microspheres was sustained for at least 42 days in vitro, and suspension of the delivery system in fibrin glue further slowed this VEGF release rate. In dogs, revascularization of the fractured femoral heads was significantly improved by a local injection of VEGF/PLGA/fibrin glue, and the quality and speed of fracture healing were significantly improved in the Experimental group than in the Control group. Our study confirmed that the VEGF/PLGA delivery system offers good angiogenic and osteogenic properties for the treatment of canine femoral neck fractures.