Wear simulation of UHMWPE for total hip replacement with a multidirectional motion pin-on-disk device: Effects of counterface material, contact area, and lubricant

Saikko, Vesa; Ahlroos, Tiina

doi:10.1002/(sici)1097-4636(200002)49:2<147::aid-jbm1>3.0.co;2-h

Cited by 53 publications

(21 citation statements)

References 18 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…As the degradation effects in the present tests were minimal compared with long duration tests, the measured μ values were much higher than those measured in longer tests. For example, the coefficient of friction in the present tests was 0.26-0.34 with 1.1 MPa, while it was as low as 0.05 after several days of running in the earlier wear tests [12,14]. At low p values, mixed lubrication mechanism probably prevailed, as μ increased with increasing p. On the other hand, above 1.1 MPa, the decrease of μ with increasing p suggested dry sliding.…”

Section: Discussionmentioning

confidence: 44%

“…From the signal of the calibrated transducer-amplifier system, the coefficient of friction could be calculated. Since the slide track radius was 5 mm and the load limit of the transducer was 30 N, the maximum friction force that could be measured was shown that if several days are run with the same serum, friction may decrease for days due to serum degradation [12,14].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Effect of contact pressure on wear and friction of ultra-high molecular weight polyethylene in multidirectional sliding

Saikko¹

2006

Proc Inst Mech Eng H

123

View full text Add to dashboard Cite

Please cite the original version: Saikko, Vesa. 2006 All material supplied via Aaltodoc is protected by copyright and other intellectual property rights, and duplication or sale of all or part of any of the repository collections is not permitted, except that material may be duplicated by you for your research use or educational purposes in electronic or print form. You must obtain permission for any other use. Electronic or print copies may not be offered, whether for sale or otherwise to anyone who is not an authorised user. ABSTRACTComputational wear models need input data from valid tribological tests. For the wear model of total hip prosthesis, the contact pressure dependence of wear and friction of ultra-high molecular weight polyethylene (UHMWPE) against polished CoCr in diluted calf serum lubricant was studied, and useful input data produced. Two test devices were designed and built, heavy load circularly translating pin-on-disk (HL-CTPOD) wear test device and HL-CTPOD friction measurement device. Both can be used with a wide range of loads. The wear surface diameter of the test pin was kept constant, 9 mm, whereas the load was varied so that the nominal contact pressure ranged from 0.1 MPa to 20 MPa. The wear factor decreased with increasing contact pressure, whereas the coefficient of friction first increased with increasing contact pressure with low pressure values, and then decreased. Up to the pressure of 2.0 MPa, the wear mechanisms and wear factors were in good agreement with clinical findings. In the critical range of 2.0-3.5 MPa, the wear mechanisms and wear factors started to differ from clinical ones, and the decrease of the wear factor steepened. The discrepancy became more and more evident as the pressure was gradually increased beyond 3.5 MPa. It appears that the pressure value of 2.0 MPa should not be exceeded in pin-on-disk wear tests that are to reproduce the clinical wear of UHMWPE acetabular cups.

show abstract

Section: Discussionmentioning

confidence: 44%

Section: Methodsmentioning

confidence: 99%

Effect of contact pressure on wear and friction of ultra-high molecular weight polyethylene in multidirectional sliding

Saikko¹

2006

Proc Inst Mech Eng H

123

View full text Add to dashboard Cite

show abstract

“…If miniature specimens were used, it would not be too difficult to pack even a much higher number of test stations than 100 into one CTPOD device, but it has been shown that the wear behaviour of a miniaturized contact surface is quite different from that of actual bearing surfaces in vivo [18]. Note that the Super-CTPOD specimens are not miniaturized.…”

Section: Discussionmentioning

confidence: 99%

“…Excessive pressure is likely to lead to abnormal thermal phenomena [18]. Overheating of the tribocontact is a pitfall to be avoided in wear testing.…”

Section: Discussionmentioning

confidence: 99%

A Hip Wear Simulator with 100 Test Stations

Saikko

2005

Proc Inst Mech Eng H

View full text Add to dashboard Cite

A novel high-capacity hip wear simulator of the pin-on-disk type was designed, built and validated. This so-called Super-CTPOD (circularly translating pin-on-disk) device has as many as 100 separate test stations, being an advanced version of the previously validated 12-station CTPOD. A validity test was done so that in all stations, the specimens and the test conditions were as similar as possible. Hence for the first time in this field, an adequate number of similar tests was done for a proper statistical analysis of wear data. The pins were conventional, gamma-sterilized ultra-high molecular weight polyethylene, and the disks were polished CoCr. The lubricant was diluted calf serum, and the test length 3 million cycles. In the course of the test, the pins became highly polished, whereas the disks remained practically Altogether, the Super-CTPOD test system was shown to be a unique combination of validity, low variation, capacity, efficiency, reliability, productivity, economy, ease of operation, and compact size.

show abstract

“…32,33 Antibiotics and fungicides are often used to retard bacterial and fungal growth in lubricants but there is no evidence indicating that this is effective in reducing the overall degradation of serum. On the contrary, Liao and co-workers 34,35 and Lu and McKellop 36 have shown that serum degradation is caused predominantly by frictional heating.…”

Section: Discussionmentioning

confidence: 99%

The effects of lubricant composition on in vitro wear testing of polymeric acetabular components

2003

View full text Add to dashboard Cite

Lubricant composition is known to affect in vitro (simulator) wear of polymeric acetabular components. Clinical acetabular components, fabricated from both ultrahigh molecular weight polyethylene (UHMWPE) and polytetrafluoroethylene (PTFE), were tested against cobalt-chromium 32-mm ball heads, with the use of various lubricants, with different compositions and concentrations of bovine and calf serum as well as hyaluronic acid, in tests which lasted one million cycles. The type of proteins and their relative concentration in the lubricant affected the wear rate of both UHMWPE and PTFE. Increasing protein concentration reduced the UHMWPE wear rate but increased the PTFE wear rate. For a given total protein concentration, increasing the albumin/globulin (A/G) ratio led to a significant reduction in the wear rate for PTFE. A similar but smaller effect was found for UHMWPE. The relative wear-rate ratio between PTFE and UHMWPE depends on both the total protein concentration and the specific protein concentration (albumin/globulin ratio). The average clinical wear rates for both PTFE and UHMWPE and the average wear-rate ratios between them were reproduced when the serum lubricant contained total protein concentration and A/G ratio within normally observed physiological ranges. It is recommended that lubricants for simulator testing be standardized to control total protein content as well as albumin/ globulin ratio.

show abstract

Wear simulation of UHMWPE for total hip replacement with a multidirectional motion pin-on-disk device: Effects of counterface material, contact area, and lubricant

Cited by 53 publications

References 18 publications

Effect of contact pressure on wear and friction of ultra-high molecular weight polyethylene in multidirectional sliding

Effect of contact pressure on wear and friction of ultra-high molecular weight polyethylene in multidirectional sliding

A Hip Wear Simulator with 100 Test Stations

The effects of lubricant composition on in vitro wear testing of polymeric acetabular components

Contact Info

Product

Resources

About