Repair of large segmental femur defects in rabbits with massive allograft combined with BMP and CPC / 中国矫形外科杂志

ABSTRACT

[Objective]To observe the bone repairing efficacy of large segmental femur defects in rabbits with calcium phosphate cement(CPC)combined with bone morphogenetic protein(BMP)and massive bone allograft,which may benefit the clinical application of large segmental bone allograft transplantation.[Method]Fifty-four New Zealand white rabbits were divided into three groups and a 2 cm femur defect was created on one side of each rabbit,followed by implantation withCPC combined with BMP and massive bone allograft(Group A),bone allograft only(Group B)and autograft transplantation(Group C).Intramedullary nails with a 3 mm diameter fixed all the grafts transplanted.The bone defect repair efficacy was evaluated by radiology and histology exam at 4,8 and 12 weeks after operation.[Result]The bone reparation capacities of allograft with CPC/BMP complex was better than that of the allograft alone after 4 ~8 weeks of transplantation,which were similar to the result of autograft transplantation.Complete bone union was achieved for all the groups after 12 weeks of operation,with better bone remodeling for group A and group C transplantation.The healing process of CPC/BMP combined with allograft transplantation was featured with large amount of bone callus forming surrounding the graft-host bone union area and the surface of allograft,which composd the extra cortical bone bridge and ingrowth(EBBI).Bone invasion,resorption as well as new bone genesis were seen in the surface of bone allograft at early stage,companied by expansion of Haversians canal,with more lanner cells,osteoblasts,osteoclasts and blood cells inside the allograft.CPC was slowly biodegraded with the bone graft resorption and new bone regeneration.[Conclusion]CPC combined with BMP can improve the bone reparation and substitution process in massive bone allograft transplantation for the treatment of large segmental bone defects.