Computational hip joint simulator for wear and heat generation

Fialho, Jorge C.; Fernandes, Paulo R.; Eça, Luís; Folgado, João

doi:10.1016/j.jbiomech.2006.12.005

Cited by 81 publications

(53 citation statements)

References 12 publications

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“…This approach yielded contact pressures in the range of 8-20 MPa for loads of 0.5-5 N. The maximum contact pressure in CoCrMo versus CoCrMo hip joints is 70 MPa, however, pressure is not distributed evenly over the contact area and this high pressure is only experienced at a small part. 17,18 In addition, an unrealistically large amount of adhesive wear occurred when the contact pressure was increased above 20 MPa in the pin-on-disc measurements.…”

Section: Methodsmentioning

confidence: 99%

Friction, lubrication, and polymer transfer between UHMWPE and CoCrMo hip‐implant materials: A fluorescence microscopy study

Crockett¹,

Roba²,

Naka³

et al. 2008

J Biomedical Materials Res

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The friction coefficients of CoCrMo sliding against UHMWPE and CoCrMo were measured in solutions of albumin and synovial fluid containing fluorescently labeled albumin. No fluorescence could be observed on the CoCrMo disc following incubation in labeled albumin or after sliding against CoCrMo. This was due to quenching of the fluorophore by the metal and indicated that a protein film thicker than 10 nm was not formed on the surface. A more complicated behavior was observed for UHMWPE sliding against CoCrMo. For each lubricating solution and at each load, a bimodal distribution of steady-state friction values was observed, the friction coefficient either remaining constant or decreasing during the early stages of the measurement. As no quenching of the fluorophores occurred on the UHMWPE surface, the fluorescence labeling method could be used to reveal polyethylene (PE) transfer and to show that it correlates with the friction coefficient: Low friction coefficients corresponded to a low density of PE spots on the CoCrMo surface. In addition, it was found that the friction coefficients for UHMWPE sliding against CoCrMo in synovial fluid were not significantly different from those in phosphate-buffered saline (PBS), but that the addition of albumin to PBS did cause a significant increase in the friction coefficient.

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Section: Methodsmentioning

confidence: 99%

Friction, lubrication, and polymer transfer between UHMWPE and CoCrMo hip‐implant materials: A fluorescence microscopy study

Crockett¹,

Roba²,

Naka³

et al. 2008

J Biomedical Materials Res

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show abstract

“…Many studies have been published on determining wear in prosthetic devices which have mainly focused on the articulating surfaces between the head and acetabular (plastic) cup [4][5][6][7][8][9][10][11]. Modern large diameter Metal-on-Metal (MoM) THRs were introduced around 1997 [12] as an option for young active patients to provide a device with reduced wear debris and risk of dislocation, greater strength and longer life than Metal-on-Plastic (MoP) types.…”

Section: Fig 1 Schematic Of Total Hip Replacement In Situmentioning

confidence: 99%

A computational approach to fretting wear prediction at the head–stem taper junction of total hip replacements

English

Ashkanfar

Rothwell

2015

Wear

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Wear is one of the main reasons for failure of modular total hip replacements. Recent evidence suggests that fretting wear occurs at the taper junction which provides fixation between the prosthesis femoral head and stem components. The fine metallic wear debris that is released can lead to adverse soft-tissue reactions which can necessitate a revision surgery. The present study proposes a computational methodology utilising an energy wear law and a 3D finite element model to predict fretting wear at the taper junction. The method is novel in that it simulates the weakening of the initial taper 'fixation' (created at impaction of the head onto the stem in surgery) due to the wearing process. The taper fixation is modelled using a contact analysis with overlapped meshes at the taper junction. The reduction in fixation is modelled by progressive removal of the overlap between components based on calculated wear. The fretting wear analysis approach has been shown to model the evolution of wear effectively; however, it has been shown that accurate, quantitative values for wear are critically dependant on mesh refinement, wear scaling factor and fraction, wear coefficient used and knowledge of the device loading history. The method has been implemented with a 3D finite element model of the taper junction of a commercial total hip replacement. This has been used to determine taper wear patterns, wear damage and wear rates which have been shown to be consistant with those found from observation and measurement of retrieved prostheses. The numerical method could be used to consider the effect of design changes and clinical technique on subsequent fretting wear in modular prosthetic devices.

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“…Most of the available literature on this subject is mostly formulated on the tribological level, in the measure that the geometrical properties (e.g., clearance size) of the hip implants are not considered as variables. The kinematic (e.g., angular velocities) and dynamic (e.g., applied forces) characteristics of the hip elements are also assumed to be constant in most of the studies [9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Spatial rigid-multibody systems with lubricated spherical clearance joints: modeling and simulation

2009

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The dynamic modeling and simulation of spatial rigid-multi-body systems with lubricated spherical joints is the main purpose of the present work. This issue is of paramount importance in the analysis and design of realistic multibody mechanical systems undergoing spatial motion.When the spherical clearance joint is modeled as dry contact; i.e., when there is no lubricant between the mechanical elements which constitute the joint, a body-to-body (typically metal-tometal) contact takes place. The joint reaction forces in this case are evaluated through a Hertzian-based contact law. A hysteretic damping factor is included in the dry contact force model to account for the energy dissipation during the contact process. The presence of a fluid lubricant avoids the direct metal-to-metal contact. In this situation, the squeeze film action, due to the relative approaching motion between the mechanical joint elements, is considered utilizing the lubrication theory associated with the spherical bearings. In both cases, the intrajoint reaction forces are evaluated as functions of the geometrical, kinematical and physical characteristics of the spherical joint. These forces are then incorporated into a standard formulation of the system's governing equations of motion as generalized external forces. A spatial four bar mechanism that includes a spherical clearance joint is considered here as example. The computational simulations are carried out with and without the fluid lubricant, and the results are compared with those obtained when the system is modeled with perfect joints only. From the general results it is observed that the system's performance with lubricant effect presents fewer peaks in the kinematic and dynamic outputs, when compared with those from the dry contact joint model.

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Computational hip joint simulator for wear and heat generation

Cited by 81 publications

References 12 publications

Friction, lubrication, and polymer transfer between UHMWPE and CoCrMo hip‐implant materials: A fluorescence microscopy study

Friction, lubrication, and polymer transfer between UHMWPE and CoCrMo hip‐implant materials: A fluorescence microscopy study

A computational approach to fretting wear prediction at the head–stem taper junction of total hip replacements

Spatial rigid-multibody systems with lubricated spherical clearance joints: modeling and simulation

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