Feasibility of prefabricated vascularized bone graft using the combination of FGF-2 and vascular bundle implantation within hydroxyapatite for osteointegration

The aim of this study was to demonstrate the feasibility of the prefabricated vascularized bone graft using an interconnected porous calcium hydroxyapatite ceramic (IP-CHA) in combination with vascular bundle implantation and basic fibroblast growth factor (FGF-2) administration in rabbit model. Thirty Japanese white rabbits were used. To make a prefabricated bone graft, the saphenous artery and vein were passed through the hole of the IP-CHA. Hundred micrograms of FGF-2 was administered into the IP-CHA before implanting the vascular bundle. First and foremost, the IP-CHA was placed subcutaneously in the medial thigh of rabbits for 4 weeks. In the experimental group, a prefabricated vascularized bone graft was used while IP-CHA alone was used in the control group. Second, the prefabricated vascularized bone graft was transplanted from the subcutaneous implanted site into the medial femoral condyle defect of the same rabbit and IP-CHA alone was implanted as the control graft in a different animal. At 4 weeks posttransplantation, bone union with host bone could be observed in the experimental group. However, the area of bone formation of the control group was significantly higher than in the experimental at 2 and 4 weeks posttransplantation. We conclude that the prefabricated vascularized bone graft when transplanted into a bone defect showed the ability for bone union with the host bone, although further studies are needed to accelerate the process of bone formation.