RESUMO
Artificial knee arthroplasty, as the most effective method for the treatment of end-stage joint diseases such as knee osteoarthritis and rheumatoid arthritis, is widely used in the field of joint surgery. At present, Finite element analysis (FEA) has been widely used in artificial knee replacement biomechanical research. This review presents the current hotspots for the application of FEA in the field of artificial knee replacement by reviewing the existing research literature and, by comparison, summarizes guidance and recommendations for artificial knee replacement surgery. We believe that lower contact stress can produce less wear and complications when components move against each other, in the process of total knee arthroplasty (TKA), mobile-bearing prostheses reduce the contact surface stress of the tibial-femoral joint compared with fixed-bearing prostheses, thus reducing the wear of the polyethylene insert. Compared with mechanical alignment, kinematic alignment reduces the maximum stress and maximum strain of the femoral component and polyethylene insert in TKA, and the lower stress reduces the wear of the joint contact surface and prolongs the life of the prosthesis. In the unicompartmental knee arthroplasty (UKA), the femoral and tibial components of mobile-bearing prostheses have better conformity, which can reduce the wear of the components, while local stress concentration caused by excessive overconformity of fixed-bearing prostheses should be avoided in UKA to prevent accelerated wear of the components, the mobile-bearing prosthesis maintained in the coronal position from 4° varus to 4° valgus and the fixed-bearing prosthesis implanted in the neutral position (0°) are recommended. In revision total knee arthroplasty (RTKA), the stem implant design should maintain the best balance between preserving bone and reducing stress around the prosthesis after implantation. Compared with cemented stems, cementless press-fit femoral stems show higher fretting, for tibial plateau bone defects, porous metal blocks are more effective in stress dispersion. Finally, compared with traditional mechanical research methods, FEA methods can yield relatively accurate simulations, which could compensate for the deficiencies of traditional mechanics in knee joint research. Thus, FEA has great potential for applications in the field of medicine.
RESUMO
Artificial prosthetic material is one of the important factors determining the effect of artificial hip replacement.There are mainly three types of interfaces in the prosthetic materials: the fixed in-terface,the friction interface,and the interface between the modular prostheses.Porous metals improve the osseointegration of the bio-logical fixed interface.High crosslinking polyethylene and composite ceramics significantly reduce the wear of the friction interface.The modular prostheses of ceramic ball head can reduce the wear particles and corrosion.However,the prosthesis loosening,wear and metal corrosion are still the most important factors affecting the medium-long term effects of artificial hip replacement.This article reviews the research progress of artificial hip prosthesis materials from the perspective of the three prosthetic interfaces.
RESUMO
Objective To study the effect of surface physical properties of different materials for the artificial joint pros -thesis interface on Mycobacterium tuberculosis adhesion .Methods The surface polishing coating , titanium coating and hydroxyapatite coating were chosen as the experimental materials to analyze the surface topography and measure the surface roughness, contact angle and surface energy .The M.tuberculosis strains were used by in vitro cultivation method and ob-served by scanning electron microscopy (SEM) to study the morphology of M.tuberculosis and the material surface adhe-sion.The influence of surface physical properties of the interface of the artificial joint prostheses on the proliferation and ad -hesion of bacteria was evaluatd .Results The titanium coating and hydroxyapatite coating materials were hydrophobic , while the surface polishing coating was hydrophilic .The contact angle and surface energy were significantly different ( P0.05)in the OD value of bacterial solution .The titanium coating had the largest amount of interface adhesion for M.tuberculosis, fol-lowed by the hydroxyapatite coating and the polishing coating .The difference between various materials was statistically sig-nificant (P<0.05).Conclusion The adhesion of M.tuberculosis in the surface of artificial joint prosthesis materials is closely related to the surface physical properties .A adhesiveness improves with surface roughness .
RESUMO
The wear debris of ultra-high molecular weight polyethylene (UHMWPE) used as a bearing material in total joint arthroplasty evokes a serious adverse biological reaction (osteolysis). In this study, therefore, the wear resistance of UHMWPE is enhanced by attaching a hydrophilic graft on the UHMWPE surface and by improving surface hardness without deteriorating the mechanical properties, which may result in the formation of lubrication film and the increased resistance to penetration, scratching or deformation during articulation. This was done by ion-implantation technique. The results showed that the wettability and the surface hardness of the modified UHMWPE by the above treatments increased due to the increased cross-linking density and hydrophilic graft attachment on the surface. The wear test was performed by a wear testing machine of pin-on-disk type. The modified UHMWPE revealed about 30~50% less volumetric wear than the control specimen. It was also shown that the volumetric wear depended not only on the optimal treatment condition but on the applied load and the sliding speed.
