Description To Wear Debris Of Artificial Joint And Its Bioreaction

Aseptic loosening is the major factor that limits the longevity of prosthetic arthroplasty. Retrieval studies have revealed cement, metallic, and UHMWPE wear debris within macrophages at the interface of loose prostheses. Bone resorption in aseptic loosening is theorized to be an inflammatory response to wear debris at the bone-prosthesis interface, and the shape of wear debris can affect respondent course. In order to find the creating rules and its effect in human joint, the hip joint simulator was used to examine the properties of artificial joint materials, and wear debris of artificial joint was got and analyzed: wear debris how to be created, what status they stay, and its bioreaction in joint. The results would be used to develop new artificial material and improve artificial joint simulator.At first wear test was done for CoCrMo-UHMWPE and Ti6Al4V-UHMWPE frictional pairs, and wear debris were got, results show that hip joint simulatorâ…¡fit the human joint work condition well.The wear debris morphology of UHMWPE, Ti alloy and human bone joint were researched, and the relations between wear debris morphology and artificial joint material property, wear mechanism and wear state were discussed. By research the relations between thickness of UHMWPE's wear debris and positive pressure of tribological system, the first grade thickness math model and the second grade thickness math model are built. The conceptions of the immutability principle and characteristic granularity of wear debris thickness are brought forward and discussed.Massing rules and distribution of wear debris was researched, the phenomenon of bi-peak distributing curve during nano-size particles agglomeration was found at first time, and figure out that in the course of massing of nano-size particle in the dispersant, soft agglomeration was not the only way, hard agglomeration was also existent.According to multiple fractal theory and the self-comparability of wear debris, the fragmentizing process of wear debris was researched in order to describe the fragmentizing course by number and matrix theories, and the multiple fractal model of fragmentizing course and distribution of wear debris were built.Radar graph fractal method and fishbone graph fractal method were introduced to describe wear debris boundaries, test results show that the fractal dimensions got by these two methods are stable and unique, prior to other fractal methods. Otherwise, the principle that radar graph fractal dimension analyzed by computer was researched.To investigate the effect of UHMWPE wear debris on the artificial joint loosening, bioreaction of wear debris for osteoblasts cultivated in vitro and in rabbit were done, and the cell culture flask was reconstructive to fit the test. Results show that UHMWPE wear debris can restrain the multiplication of osteoblasts, and stimulate macrophage cell to release inflammation factors increased, induced osteoclasts inborn and proliferate, effect on the process of aseptic loosening.