The analysis of the dimple arrangement of the artificial hip joint to the performance of lubrication

Abstract

Artificial hip joint surgery is one of the most successful methods used to restore the functioning of damaged hip bones. But there are obstacles to the use of artificial hip bone, which is the amount of friction occurring and wears. To overcome these obstacles, a surface of the artificial hip joint is modified by adding dimples in order to minimize the contact pressure of solid and to reduce friction and wear. The purpose of this study is to determine a better of lubrication performance with the variations of the dimple arrangements under the normal walking condition. Simulation results have already exited the point of convergence studies, and the obtained results are such as hydrodynamic pressure, contact pressure, and the film thickness of the lubricant with the variations of the number and pitch dimples. The results of the CSM method under dry condition, it shows that the addition of surface with dimples has a positive effect to reduce the contact pressure and indirectly reduce wear. The maximum surface contact pressure is 54.84 MPa with dimple and 94.22 MPa without a dimple. The results of the FSI method under lubrication condition, it was found that the variation of 7 dimples with a dimple pitch of 500 μm has the best lubrication performance. The hydrodynamic pressure is 0.73 Pa, the contact pressure is 0.42 Pa, and the film thickness of the lubricant is 29.59 μm. The increase of film thickness that occurs due to hydrodynamic pressure will cause the fluid lift force to withstand the loading of the solid structure.

The Effect of Bottom Profile Dimples on the Femoral Head on Wear in Metal-on-Metal Total Hip Arthroplasty

“…Furthermore, as shown in Figure 9 , the textured surface can withstand local wear, as evidenced by the distribution of the contact pressure after 2 × 10 6 cycles, which was not too wide compared to the model without dimples. The explanation for the results presented is consistent with the available literature, which suggests various positive effects of textured surface applications on contact surfaces [ 9 , 10 , 12 , 13 , 14 ].…”

“…Total hip arthroplasty with a textured surface can reduce the surface contact area, and decrease the adhesion wear and coefficient of friction [ 8 ]. Dimples serve to trap wear particles, thereby preventing abrasive wear of the contact surface by a third object, and generating hydrodynamic pressure to provide additional lift [ 9 , 10 ]. Various studies have also shown the positive effect of surface texturing on bearings in improving the tribological performance, both theoretically and experimentally [ 11 , 12 , 13 , 14 ].…”

“…Some parameters that influence adding dimples to reduce wear in total hip arthroplasty, such as shape, diameter, depth, distance, direction, and arrangement, have been investigated previously in order to maximize the effect of adding dimples, and to find the optimal parameters. Even so, until now, there has been no research to determine the optimum conditions for various parameters; these are usually investigated by trial and error [ 9 , 10 ]. One of the relatively new parameters being studied by many researchers is the bottom profile geometry of dimples.…”

“…The finite element method, as a computational analysis tool, has been widely applied to various total hip arthroplasty studies, minimizing the need for costly experiments. To shorten this time-consuming computational process, many studies, such as those by Cosmic et al [ 15 ], Liu et al [ 16 ], Jamari et al [ 17 ], Harun et al [ 2 ], Meng et al [ 6 ], and Basri et al [ 9 , 10 ], have used simplified loading, with vertical loads that did not represent the true physiological hip joint. This may limit the actual results, including analysis of the effect of adding dimples on wear, which needs to consider gait loading and the range of motion of the hip joint in actual conditions.…”

“…Total hip arthroplasty wear modelling by previous researchers has mostly used synovial fluids as lubrication, to assess the actual conditions [ 6 , 9 , 10 ]. Dry contact, which reflects boundary lubrication conditions, is also essential, and contact pressure can be seen more clearly under dry contact conditions.…”