Potential thermal artifacts in hip joint wear simulators

Lu, Zhen; McKellop, Harry A.; Liao, Peter; Benya, Paul D.

doi:10.1002/(sici)1097-4636(1999)48:4<458::aid-jbm9>3.0.co;2-b

Cited by 57 publications

(32 citation statements)

References 14 publications

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“…However, in this simulator study these types of third bodies were not present. Some studies reported the formation of calcium-phosphate layers on the articulating metallic surfaces [24], which may possibly chip off during articulation and cause third body wear.…”

Section: Discussionmentioning

confidence: 99%

Wear in total knee arthroplasty—just a question of polyethylene?

Kretzer

Reinders

Sonntag

et al. 2013

International Orthopaedics (SICOT)

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Purpose Biological reactions against wear particles are a common cause for revision in total knee arthroplasty. To date, wear has mainly been attributed to polyethylene. However, the implants have large metallic surfaces that also could potentially lead to metal wear products (metal ions and debris). The aim of this study was to determine the local release of cobalt, chromium, molybdenum and titanium in total knee arthroplasty during a standard knee wear test. Methods Four moderately conforming fixed-bearing implants were subjected to physiological loadings and motions for 5×10 6 walking cycles in a knee wear simulator. Polyethylene wear was determined gravimetrically and the release of metallic wear products was measured using high resolutioninductively coupled plasma-mass spectrometry. Results A polyethylene wear rate of 7.28±0.27 mg/10 6 cycles was determined and the cumulative mass of released metals measured 1.63±0.28 mg for cobalt, 0.47±0.06 mg for chromium, 0.42±0.06 mg for molybdenum and 1.28±0.14 mg for titanium. Conclusion For other metallic implants such as metal-on-metal total hip arthroplasty, the metal wear products can interact with the immune system, potentially leading to immunotoxic effects. In this study about 12 % by weight of the wear products were metallic, and these particles and ions may become clinically relevant for patients sensitive to these materials in particular. Non-metallic materials (e.g. ceramics or suitable coatings) may be considered for an alternative treatment for those patients.

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Section: Discussionmentioning

confidence: 99%

Wear in total knee arthroplasty—just a question of polyethylene?

Kretzer

Reinders

Sonntag

et al. 2013

International Orthopaedics (SICOT)

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“…This may be the result of thermal heating at the articulating surfaces when testing at 2 Hz. PEEK is considered a thermal insulator (thermal conductivity of 0.25 W/mK) as compared to the more common material of CoCr (thermal conductivity of 18 W/mK), and this may have resulted in denaturization of the proteinaceous lubricant, potentially forming a protective triobolayer [27][28][29]. This is supported by the results for Group 3, where a reduced protein content of 5 g/L and a decrease in the lubricant temperature to 23°C was performed to reduce any thermal artifact and further minimize protein denaturization.…”

Section: Discussionmentioning

confidence: 99%

The use of self-mating PEEK as an alternative bearing material for cervical disc arthroplasty: a comparison of different simulator inputs and tribological environments

Brown

Bao

2012

Eur Spine J

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Purpose The hypothesis for this study was that the simulated wear behavior of a hydroxyapatite coated, selfmating PEEK cervical disc arthroplasty device would be dependent on the simulated testing environment. Methods Five groups of devices were evaluated under suggested ASTM and ISO load and motion profiles. The groups utilized different testing frequencies and protein content of simulator fluid, in addition to assessing the potential for third body wear. The average wear rates were determined using linear regression analysis with a generalized estimating equation. Significant differences between groups were determined using the Wald's test. Results The simulated wear behavior was shown to be highly dependent on the testing environment, where protein content more than decreasing the cyclic loading frequency resulted in increased wear, but was not dependent on the suggested load and motion profiles. It was demonstrated that a self-mating PEEK cervical disc arthroplasty device has wear rates that are similar to existing material combinations for cervical disc arthroplasty. Conclusions This study showed that at a time when data from retrieval analyses is deficient, it is important to test the wear resistance of cervical disc arthroplasty devices under various conditions. Long-term clinical results and ongoing implant retrievals are required for validation between clinical performance and simulator inputs.

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“…[9][10][11][12][13]29,30 The articulating surfaces were subjected to a biaxial rocking motion with a peak load of 2.1 kN applied at 1.13 Hz. Further details of the simulator conditions have been provided in earlier publications.…”

Section: Hip Simulatormentioning

confidence: 99%

Effects of digestion protocols on the isolation and characterization of metal-metal wear particles. I. Analysis of particle size and shape

Catelas

Bobyn

Medley

et al. 2001

J. Biomed. Mater. Res.

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Isolation of metal wear particles from hip simulator lubricants or tissues surrounding implants is a challenging problem because of small particle size, their tendency to agglomerate, and their potential for chemical degradation by digestion reagents. To provide realistic measurements of size, shape, and composition of metal wear particles, it is important to optimize particle isolation and minimize particle changes due to the effects of the reagents. In this study (Part I of II), transmission electron microscopy (TEM) was used to examine and compare the effects of different isolation protocols, using enzymes or alkaline solutions, on the size and shape of three different types of cobalt-based alloy particles produced from metal-metal bearings. The effect on particle composition was examined in a subsequent study (Part II). Large particles (<1200 nm) were generated by dry abrasion of CoCrMo alloy against itself and small particles (<300 nm) were generated by hip simulator testing of a metal-metal implant pair in the presence of either distilled-deionized water or a 95% bovine serum solution. The reagents changed particle size and to a lesser extent particle shape. For both large particles and small particles generated in water, the changes in size were more extensive after alkaline than after enzymatic protocols and increased with alkaline concentration and time in solution, up to twofold at 2 h and threefold at 48 h. However, when isolating particles from 95% serum, an initial protective effect of serum proteins and/or lipids was observed. Because of this protective effect, there was no significant difference in particle size and shape for both oval and needle-shaped particles after 2 h in 2N KOH and after enzymatic treatments. However, round particles were significantly smaller after 2 h in 2N KOH than after enzymatic treatments. Particle composition may also have been affected by the 2N KOH treatment, as suggested by a difference in particle contrast under TEM, an issue examined in detail in Part II.

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Potential thermal artifacts in hip joint wear simulators

Cited by 57 publications

References 14 publications

Wear in total knee arthroplasty—just a question of polyethylene?

Wear in total knee arthroplasty—just a question of polyethylene?

The use of self-mating PEEK as an alternative bearing material for cervical disc arthroplasty: a comparison of different simulator inputs and tribological environments

Effects of digestion protocols on the isolation and characterization of metal-metal wear particles. I. Analysis of particle size and shape

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