Experimental study on the cuff of muscle tissue of vascularized fibular autografts in the transplantation combined with massive allograft

Objective To investigate the natural progressing morphology and characteristic of the cuff of muscle tissue of vascularized fibular autografts,in the transplantation combined with massive allograft. Methods The bone massive defect animal models were made adult dogs at the shaft of tibia below the tibial tuberosity which remove 3.0 cm of diaphysis and periosteum.Thirty-six dogs were randomly divided into experimental and control groups.The bone defects were filled with either a frozen allograft combined with the ipsilateral vascularised fibular in experimental group,or a massive frozen allogeneic cortical bone alone in control group.Outcome assessment included X-ray,bone scintigraphy examinations,gross specimen as well as histological studies at the 1,2,3,4 months postoperative. Results In the same period,radiographic evaluation of the allogeneic cortical bone and junctions between allograft bone revealed significantly allograft bone resorption,Greater new bone fromation and larger osteon radii in experimental group compared to control group.The healing rates of osteosynthesis was 83.3% by 4 month in experimental group,while no connection can be observed in control group.ECT showed that,in the same period,bone metabolism was more active in experimental group compared to cntrol group.bone metabolism were more active at 1,2 months,and it reached its peak by 2 months,then it had a decreasing tendency at 3,4 months postoperative.Histological observation showed,compared to control group,significantly higher resorption and osteogenesis were detected in the internal wall of the medullary cavity and Haversian canals in experimental group.At the 4 month,in transverse sections of allografts,the gaps between inner cortical areas of allograft and fibular autograft were filled with annular callus,which was put in order looking like ladder.The callus near inner cortical areas of allograft was mature,and most of which was lamellar bone being made up of mature osteocyte.While there was premature callus in the place near the fibular,which were primarily made up of osteoblasts and osteocytes.The fiber of periosteum and surrounding skeletal muscle tissue of vascularized fibular autografts disappeared in the medullary cavity of massive allogeneic cortical bone. Conclusion Ultimately,the cuff of muscle tissue of vascularized fibular autografts is ossification in the tranplantation combined with massive allograft.