Surface characterization of metal-on-metal hip implants tested in a hip simulator

Wang, A; Yue, Steve; Bobyn, J. D.; Chan, Frank; Medley, John B.

doi:10.1016/s0043-1648(98)00384-6

Cited by 46 publications

(27 citation statements)

References 23 publications

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“…Layers with a similar appearance have been observed in vivo 12 and recently reported in a simulator study by Wang et al 23 The latter found a layer thickness of approximately 30 to 40 nm. The layers were thinner at the apex than at the periphery of the articulation.…”

Section: Wear Mechanismssupporting

confidence: 80%

“…Wang et al assumed that the layered surface derived either from delamination by surface fatigue or from material transfer from the opposing surface by adhesion. 23 After 30 h of testing, no comparable appearances of delamination or surface fatigue were found in the present study. Therefore, another mechanism is proposed, leading to the formation of the observed layers.…”

Section: Wear Mechanismscontrasting

confidence: 48%

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Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation

et al. 2004

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To control and minimize wear of metal-on-metal hip joints it is essential to understand the mechanisms of debris generation. In vivo, mainly nanosize globular and needle-shaped particles are found. These can neither stem from the action of abrasion nor from tribochemical reactions. In this study the acting wear mechanisms have been first identified on the surface by means of scanning electron microscopy (SEM). Afterwards, the microstructures of the subsurface regions of explants have been investigated using a transmission electron microscope (TEM). Observation of the subsurface gave additional insight about the microstructural changes of cobalt-base alloys subjected to wear. At some distance from the surface, a network of stacking faults and hexagonal ⑀-martensite was found strengthening the bulk material. This microstructure changed into a nanocrystalline type moving closer towards the surface. A comparison of in vivo debris size and grain size of the surface suggests that the globular wear particles result from torn off nanocrystals, while the needle shaped particles are generated by fractured ⑀-martensite. Identified cracks, propagating through the nanocrystalline layer, further support these findings. Thus, it is suggested that the dominating mechanism of particle generation for metal-on-metal joints is surface fatigue within a nanocrystalline surface layer.

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Section: Wear Mechanismssupporting

confidence: 80%

Section: Wear Mechanismscontrasting

confidence: 48%

Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation

et al. 2004

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“…Wear studies, in both hip simulators and pin-on-disc tests, have shown a correlation between the protein content and wear [10,11]. Examination of metal implant surfaces from both in vitro and in vivo function has shown that proteins are deposited on the surfaces [12,13] and are implicated in boundary film formation [10].…”

Section: Introductionmentioning

confidence: 99%

Inlet protein aggregation: a new mechanism for lubricating film formation with model synovial fluids

Fan

Myant

Underwood

et al. 2011

Proc Inst Mech Eng H

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This paper reports a fundamental study of lubricant film formation with model synovial fluid components (proteins) and bovine serum (BS). The objective was to investigate the role of proteins in the lubrication process. Film thickness was measured by optical interferometry in a ball-on-disc device (mean speed range of 2-60 mm/s). A commercial cobalt-chromium (CoCrMo) metal femoral head was used as the stationary component. The results for BS showed complex time-dependent behaviour, which was not representative of a simple fluid. After a few minutes sliding BS formed a thin adherent film of 10-20 nm, which was attributed to protein absorbance at the surface. This layer was augmented by a hydrodynamic film, which often increased at slow speeds. At the end of the test deposited surface layers of 20-50 nm were measured. Imaging of the contact showed that at slow speeds an apparent 'phase boundary' formed in the inlet just in front of the Hertzian zone. This was associated with the formation of a reservoir of high-viscosity material that periodically moved through the contact forming a much thicker film. The study shows that proteins play an important role in the film-forming process and current lubrication models do not capture these mechanisms.

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“…1,2) On the other hand, Co-Cr-Mo wrought alloys consist of fine and uniform grains and show better tensile strength, yield strength and elongation than cast alloys and heat-treated alloy. 2,3) The wrought alloys also contain fine carbide structures. 4) Excellent wear resistance of the Co-Cr-Mo alloys is attributable to these carbide structure found in both cast and wrought alloys.…”

Section: Introductionmentioning

confidence: 99%

Friction-Wear Properties of Nickel-Free Co–Cr–Mo Alloy in a Simulated Body Fluid

et al. 2005

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Friction-wear properties of a Co-29 mass%Cr-6 mass%Mo alloy (ASTM F799-95) but reducing the amount of nickel were evaluated with friction-wear test using a pin-on-flat type reciprocating friction tester in air and phosphate buffered saline, PBS(À), as a quasi-biological environment under applied stress of 1.0, 3.5 and 5.0 MPa to understand the performance of this alloy for metal-on-metal type artificial hip joints. In addition, metal ions dissolved in PBS(À) after the test was quantified. As a result, wear loss in PBS(À) is much smaller than that in air and increases with the increase of applied stress in both air and PBS(À), while the coefficient of friction in steady state during the test is larger in PBS(À) than in air, according to lubrication behavior of wear debris and PBS(À). Wear damage in PBS(À) is smaller than that in air, however more small scale of irregularity is observed in PBS(À) than that in air. Nickel and molybdenum are preferentially dissolved during the test.

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Surface characterization of metal-on-metal hip implants tested in a hip simulator

Cited by 46 publications

References 23 publications

Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation

Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation

Inlet protein aggregation: a new mechanism for lubricating film formation with model synovial fluids

Friction-Wear Properties of Nickel-Free Co–Cr–Mo Alloy in a Simulated Body Fluid

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Surface characterization of metal-on-metal hip implants tested in a hip simulator

Cited by 46 publications

References 23 publications

Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation

Subsurface microstructure of metal‐on‐metal hip joints and its relationship to wear particle generation

Inlet protein aggregation: a new mechanism for lubricating film formation with model synovial fluids

Friction-Wear Properties of Nickel-Free Co&ndash;Cr&ndash;Mo Alloy in a Simulated Body Fluid

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Product

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Friction-Wear Properties of Nickel-Free Co–Cr–Mo Alloy in a Simulated Body Fluid