| Background:The "low friction arthroplasty" theory proposed by John Charnley laid the foundation for the development of modern total hip arthroplasty.To date, total hip arthroplasty has been one of the most succeed operation in implanting surgery. There are more than 1,000,000 patients receiving the operation each year. THA can help patients to get rid of the suffering from joint diseases, restore the shape and function of the joint, and improve the mobility and life quality. Although, the prosthesis wear and wear debris have always been the crucial factors affecting the longevity of prosthesis. Wear debris generated by prostheses are able to active the body immune system and cause cellular response resulting in the release of cytokines,which can promote the osteoclast generation and inhibit the osteoblast maturity. The course will induce periprostheses osteolysis and aseptic loosening, which result in the failure of THA. Further researches have demonstrated that the wear debris constitution, size, shape, number, surface character and volume have great influence on cellular reaction. Therefore, the accurate wear debris parameter and character are assistant to evaluate the current and new biomaterial applied on artificial joint surfaces. The early artificial joint simulator tests were carried out in 1980s at abroad. The simulator tests, which were performed relatively lately in the domestic, attached much more importance on wear coefficient, wear volume and wear rate of prostheses in different lubrication. There were little research focusing on the parameter information of debris. In the experiment, the wear debris were analyzed qualitatively and quantitatively in different methods.Objective:To identify the characteristics of wear particles generated by Ti alloy femoral head coated by nanometer-carbon multilayer film on hip simulator. The result is expected to be compared with control groups.Methods:Three groups of artificial femoral head were studied in the research. Two femoral heads of each group were examined. Group A, CoCrMo alloy femoral head against ultra-high molecular weight polyethylene(UHMWPE) acetabular cup (Zimmer, America). Group B, Ti alloy femoral head with diamond-like carbon coating against UHMWPE acetabular cup. Group C, CoCrMo alloy femoral head against UHMWPE acetabular cup (Jinghang, China). Fetal bovine serum lubricant was collected respectively from each group after 0.33million circles (mc).Then the bovine serum was digested by adding acid and filtered through polycarbonate. The characteristics of particles of each group were determined by scanning electron microscope-energy dispersion X-ray analysis (SEM-EDX). The size, shape and number of particles were measured with Image-Pro Plus6.0 according SEM pictures.Results:The energy dispersion X-ray analysis(EDX) showed the main element is carbon. There was no marked metal element detected(such as Co, Cr, Mo, Ti). Over 60% of the particles are globe-like in each group. The particle size varied from 0.1 to 40μm, most of which ranged from 0.1 to 1μm. Particles with diameter over 1μm have a large proportion in volume.The number of particles on filter in group B was less than control groups while the volume was bigger in group B.Conclusions:The wear particles in group B are predominately UHMWPE particles. Compared with control groups, artificial femoral heads with nanometer-carbon multilayer coating, which cause lower debris production less than 1 μm, produce less wear particles in number on the filter. |
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