| The loosening of the fixed interface after artificial joint replacement is one of the main reasons for the failure of artificial joints.Due to the longer recovery time and lower interfacial bonding strength of biological fixation,its development is greatly limited.Based on the reconstruction function of bone tissue under appropriate mechanical fretting stimulation,this paper selected the active bone-inactive prosthetic material as the binding sample,and proposed to apply mechanical fretting stimulation on the fixed interface to explore the effect of different stimulation parameters on bone growth and interface bonding quality.The results of this study are of great significance for shortening the recovery time after artificial joint replacement,improving the stability quality of the fixation interface of artificial joint and prolonging the life of artificial joint prosthesis.In this thesis,we first constructed an in vitro aseptic culture system,set up an in vitro aseptic experimental environment,and optimized the preparation of the medium.The experimental verification provided a good prerequisite for the smooth development of the in vitro bone tissue culture experiment and the binding interface bone growth experiment.This thesis took active rat bone tissue/artificial joint titanium bead-coated titanium alloy as the research object.Based on two methods of alternating compression fretting stimulation and alternating tangential fretting stimulation,explored the influence of different culture period,compression load,tangential fretting amplitude and normal load and other parameters on the growth rate of bone tissue and the strength of the bonding interface,and analyzed the bone growth mechanism at the interface of titanium bead coating of artificial joint.The experimental results of alternating compression fretting stimulation showed that the interface bonding force was the largest(0.1±0.005N)under the condition of 0-4N compression load in the culture period of 15 days.In the bone tissue samples,the bone trabeculae were closely arranged,the structure was complete.The number of bone cells,calcium salt granules,mature collagen fibers,fibrous connective tissue and chondrocytes were in the best state.On the surface of the titanium bead coating,the nuclei were evenly distributed and tightly arranged,and the calcified new bone tissue was also closely adhered.These results indicated that the fretting stimulation can promote the growth of bone tissue and the quality optimization of the binding interface.The experimental results of alternating tangential fretting stimulation showed that the maximum interface bonding force was 0.145±0.007 N under the conditions of fretting amplitude of 40?m and normal load of 5N.In the bone tissue samples,the trabecular bone area was larger.There were a large number of various types of cells which were conducive to bone reconstruction and bone regeneration.These cells stretched and migrated,deposited orderly along the arc surface of the titanium beads,and mineralized.This indicated that the fretting stimulation can promote bone growth and improve the quality of interface bonding.Based on the experimental study of mechanical fretting stimulation in two different ways,the bone growth mechanism at the interface of the titanium bead coating of the artificial joint was explored.When appropriate fretting stimulation was given to the active bone-inactive prosthetic material interface,the uneven,high-porosity titanium bead surface provided a larger contact surface for material exchange,and also provided a good pore structure.A large number of osteoblasts surrounded the titanium beads to survive and secreted a large number of collagen fibers.After gradually maturation,they mineralized with calcium salt particles to form new bone tissue,thereby enhancing the bonding strength and stability of the interface between the titanium bead coating and the bone tissue.The paper has 45 pictures,11 tables,and 99 references. |
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