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Abstract The purpose of this research is to develop data‐driven machine learning (ML) models capable of estimating the specific wear rate of ultra‐high molecular weight polyethylene (UHMWPE) used in hip replacement implants. The results of the data‐driven models are demonstrating a high level of consistency with the experimental findings acquired from the pin‐on‐disk (POD) trials. With a performance evaluation of 0.06 mean absolute error (MAE), 0.17 Root Mean Square Error (RMSE), and 0.96 R2, the Random Forest Regression is found to be the best model. Another machine learning model, called Gradient Boosting Regression, is also found to possess satisfactory predictive performance by having an MAE of 0.09, RMSE of 0.24, and R2 of 0.96. According to the findings of a parametric analysis that made use of an ML model, the surface texture geometry has a substantial dependence on the wear behaviour of UHMWPE bearings that are used in hip replacement implants. This strategy has the potential to enhance experiment design and lessen the necessity for time‐consuming POD trials for the purpose of assessing the wear of hip replacement implants.

Abstract Ti15Mo alloy has been regarded as one of the most potential biomedical materials due to its excellent performance. However, the low hardness and poor wear resistance of titanium alloy limit the further application. Therefore, high temperature solid carburising technology was performed on the surface of Ti15Mo alloys to prepare titanium carbide (TiC) coating with graphene (G) as the carburising agent. The microstructure, mechanical properties, and tribological properties of TiC coating under different lubricants were investigated. Results showed that TiC coating was closely bonded to the titanium substrate. The maximum thickness of TiC coating treated with 1150°C was approximately 184.02 μm, and the microhardness of alloys treated with 1100°C can achieve 1221.5 HV. All modified Ti15Mo alloys showed improved tribological performance compared to the original samples. The wear mechanisms of modified Ti15Mo alloys were abrasive wear and adhesive wear under the SBF lubricant, and the TiC coating was slightly peeled off. The overall friction coefficient and wear rate under 25% calf serum lubricant were lower than the SBF lubricant, and surface scratches were almost absent, and slight abrasive wear and adhesive wear occurred on the surface.

Poly (vinyl alcohol) (PVA) hydrogel with high water content is the candidate material for artificial cartilage. PVA hydrogels prepared by freeze-thawing (FT) method (PVA-FT gel), cast-drying (CD) method (PVA-CD gel) and hybrid method of FT and CD (PVA-hybrid gel) were developed and their friction and wear behaviors were evaluated. Sliding pairs of a cobalt-chromium-molybdenum alloy or alumina ceramic ball and a PVA hydrogel plate were tested in reciprocating friction test. Ultra-pure water and simulated synovial fluid were used as lubricants for friction test. PVA-FT gel showed high friction and severe wear in ultra-pure water. Friction coefficient of PVA-CD gel in ultra-pure water was quite low such as about 0.005, but scratches were observed on the surface of PVA-CD gel. PVA-hybrid gel lubricated in ultra-pure water showed low friction such as 0.004, and intact surface structure of PVA-hybrid gel remained after friction test. Simulated synovial fluid contributed to the improvement of lubrication property of all PVA hydrogels and PVA-hybrid gel showed the lowest friction coefficient such as 0.003 and minimum wear. These results indicated that PVA-hybrid gel has a great potential as the material for artificial joint.

Ultra-high molecular weight polyethylene (UHMWPE) wear particles from artificial joints induce osteolysis and the subsequent loosening of implants. Studies have reported that particles in the size range of 0.1–10 μm are the most biologically active in macrophage immune response. To develop prosthetic joints with greater longevity and durability, it is crucial to understand the deleterious effects of wear particles. In this study, to evaluate the effects of particle size on the activities of human monocyte-derived macrophages (HMDMs), seven differently sized particles of polymethylmethacrylate (PMMA), in the range of 0.1–20 μm, were prepared. Viability and the secretion of cytokines were evaluated after phagocytosis of each size particles by HMDMs. Differences in the viability of HMDMs after phagocytosis of particles sized 0.16–9.6 μm were statistically significant. Proinflammatory cytokine production of both tumor necrosis factor-α and interleukin-6 by HMDMs was strongly induced by 0.8 μm PMMA particles. Consistent with the fact that macrophages are known to respond to pathogens measuring approximately 1.0 μm in size, in this study, PMMA particles measuring 0.8 μm in size induced an immune response. This work provides fundamental data for the designing of surface profiles of prosthetic joints, Which may expect the lower incidence of immune response.

The relationship between the wear behaviour of an ultra-high-molecular-weight polyethylene (GUR1050) pin and surface profile of a Co-28Cr-6Mo alloy (ASTM F-75) disc was investigated. Tribological tests have been performed by pin-on-disc wear testing machine with multi-directional pathways, obtaining the influence of micro slurry-jet erosion (MSE) processed Co–Cr–Mo alloy. The specific wear and the wear particles have been investigated. It was elucidated that the Co–Cr–Mo alloy surface processed by MSE influenced the specific wear rate of polyethylene; however, the morphological aspect of polyethylene wear particles was not drastically changed. The wear particles isolated from the lubricating liquid were added to a culture medium, and human monocyte-derived macrophages were incubated by using an upright/inverted method. The production of TNF-α and IL-6 seemed to have a correlation with the amount of wear particles added, however, the influence of particle size on the production of TNF-α and IL-6 was not obvious. This means that the improvements for the incubation method, i.e. upright/inverted method, need further investigation for the accurate analysis.