| BackgroundWith the rapid development of modern traffic and construction, traumatic patients with fractures is increasing gradually.Although many innovative internal fixation device are performed,so many fractures get a nonunion or delayed union at a level of 5%~10%. How to shortening the healing process, restoration the function of the injured limbs more early will make significant profit for the patients and the society.Without in any way denying the massive contribution of the Association for Osteosynthesis (AO)school in establishing the principles and practice of rigid internal fixation of fractures, there are inherent drawbacks to the system such as decay, electrolyte, stress shielding and et al. The procedure has an unforgiving nature and if surgical technique or the complexity of the fracture render the reduction and fixation less than perfect, nonunion , refracture and fatigue breakage of the plate may follow. Rigidity of fixation totally immobilizes the fracture, abolishes the natural process of healing by external callus and dictates that union proceeds by process of cortical repair that has been termed primary bone union. This process , however ,is frequently prolonged the bone healing. Stress protection osteoporosis predisposes the bone to refractures or plate breakage. These accepted drawbacks to the system of rigid metal fixation have led to a search for materials that would permit stable but semirigid fixation, which named BO (Biological Osteosynthesis) , specially upholded nowaday.One of such materials, Continuous Carbon ?fiber Reinforced Polyolefin Polymer (CRPP) may be an ideal option for the fixation system. As an internal fixation of fracture, CFRP have more distinguished virtue such as an elastic modular suitable to the cortial bone , strong anti-fatigue , strong intensity for reduce, appropriate ductility, reabsorbtion strength when unloaded, being more light, nocorrosion, Roentgenographic lucent which makes observation the healing conveniently, no interaction with MRI and CT and et al. So the products made by CFRP are sure to be a bright prospect of medical application .ObjectiveWe undertook this study to evaluate the characteristic of CRPP as fracture fixation for the purpose of further development and clinical application for the material.Methods1. According to the standard of GB/T 16886. 3-1997,seven items were used to evaluate biocompatibility of the material: Hemolysis test Pyrogen test Skin irritation test Cytotoxicity test Ames test In vitro chromosome aberration test Bone marrow cells micronuclei test. In vivo embedding experiment to found if there were any inflammatory reaction or immunological rejection and the change of the materials itself: Muscle embedding experiment Plate surface contact experiment Medullary cavity embedding experiment.2. In a series of 66 rabbits, transvers fracture model with 3 mm bone defect of tibial diaphysis was made by a self designed cyclic- saw. Afer reduction,left tibia was plated with a 6-holes Carbon-fiber Reinforced Polyolefm Polymer Plate (CFRP) and the right with a stainless steel plate as control, both without compression. We observed the healing process of the fractures with X-ray,Computed Tomography, decalcification and none decalcification tissue section, immunohistochemistry, fluorescent pigmenting ,electron microscope and et al.3. With biomechanics test, four kinds such as draw-extension, bending, compression, shearing testing were conduced to collect the stress,strain,and migration of the specimen.then to calculate the intensity,elastic modular and extention rate. For implanted experiment,bending testing and torsion testing were applied on the healing tibia callus during healing time,to illustrate the different effect of the two kinds of internal fixation.4. For long-term implantation, we observe the effect of the two different fixation with the thick and the osteoporosity of the cortical bone infra-plate, the collagenarrangement and CT value, by microscope, image analysis, polarized ligh...
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