Experimental Study Of Repairing Femur Head Necrosis With Tissue Engineering Bone

Objective To observe the repairing effectiveness of tissue engineering bone on bone defect of rabbit femur head necrosis.Methods Primary osteoblastic cells were obtained from the calvaria of newborn rabbits by methods of collagenase digesting and bone chip adhesion and then co-cultured with HA/β-TCP ceramic in vitro; 14 rabbits were drilled holes and insulted with 95% alcohol in bilateral femur heads and implanted with TE bone, only HA/β-TCP or not treated.Their hips were randomly devided into 3 groups: A-cntroll group, B-only HA/β-TCP implanted group and C-tissue engineering bone implanted group. Imageology and histopathology changes were studied at 4, 8, 12 weeks with X-ray, CT and HE staining. Area of bone defect and trabecula bone volume were studied postoperatively.Results Two methods to culture osteoblasts in vitro were satisfactory and massive osteoblasts were harvested. The alkaline phosphatase staining of osteoblasts is positive in the third generation OBs. Scanning electron microscope detection shows osteoblasts generate, disintegrate and secrete bone matrix constantly when co-cultured with HA/β-TCP.Roentgenographic and CT changes: In group C, high density with a photic zone around is shown in the femoral heads implanted with tissue engineering bone at 4th week that had no difference from those in group B; At 8th week the density of tissue engineering bone is lower than those in group B and the photic zone was vague; At 12th week there was no difference between the area implanted with TE bone and the normal bone on the whole. There was no collapse of femoral head in group C.Histopathologic changes: In group C a bone formation reaction zone emerged around the polymer 4 weeks after the operation. New bone was detected in the experimental area and on the surface of the tissue engineering bone and the scaffold almost all degraded in group C 12 weeks postoperatively.There were statistically significant differences of the size of bone defect and trabecular bone volume between group A and the other groups 12 weeks postoperatively.Conclution HA/β-TCP has bone conductivity and bone inductivity, is one of ideal scaffolds for tissue engineering. The animal model of FHN is similar to cystic change of humanFHN and can be used in the study of FHN. Tissue engineering bone can enhance the repairment of bone defect of femur head necrosis and prevent collapse of femur head.