Slide track analysis of eight contemporary hip simulator designs

Calonius, Olof; Saikko, Vesa

doi:10.1016/s0021-9290(02)00171-9

Cited by 54 publications

(59 citation statements)

References 13 publications

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“…The motion in the Durham simulator is sinusoidal flexion-extension of the head (range 45°) and sinusoidal internal-external rotation of the cup (range 10°) with a phase difference of π/2. Hence the shape of the slide tracks on the load-bearing surface (which is small under normal test conditions) is a straight line on the head and a very narrow figure of eight on the cup [23].…”

Section: Discussionmentioning

confidence: 98%

Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup

Saikko

2016

Tribology International

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This is an electronic reprint of the original article. This reprint may differ from the original in pagination and typographic detail. Author(s):Saikko, Vesa Title: Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup 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. AbstractIn some earlier hip simulator studies of large-diameter metal-on-metal (MoM) hip prostheses high, unexplained variation in wear has been observed. In the present study it was found that high variation occurs when the tribological endurance limit of the MoM device in question is being approached. When the limit is exceeded, high wear takes place uniformly, and the variation is low. Below the limit, both the wear and its variation are low. The endurance limit was exceeded by increasing the peak load from 2 kN to 3 kN, to simulate obesity. The acetabular cup inclination angle was high, 70°. Potential clinical wear problems can be predicted by hip simulator studies provided that relevant adverse test conditions are included.

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Section: Discussionmentioning

confidence: 98%

Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup

Saikko

2016

Tribology International

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“…4 It was shown that in the different hip simulators that have been used to study the wear of total hip prostheses, the slide track patterns varied greatly. 5 This may partly explain the large differences in the observed wear rates. The same may hold true clinically.…”

Section: Introductionmentioning

confidence: 98%

“…The size and shape of an individual track depends on the position relative to the rotation axes, the rotation waveforms, and the Euler sequence of rotations. 4,5 Hence, a hip simulator cannot be used to study the relationship between a certain slide track shape and wear rate, because the entire slide track pattern is involved in the production of the observed total wear.…”

Section: Introductionmentioning

confidence: 99%

Effect of slide track shape on the wear of ultra‐high molecular weight polyethylene in a pin‐on‐disk wear simulation of total hip prosthesis

Saikko¹,

Calonius²,

Keränen

2004

J Biomed Mater Res

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Prosthetic joints appear to show a strong relationship between the type of relative motion and wear, requiring careful consideration in the design of wear simulators. This relationship was studied with a 12-station pin-on-disk device, specifically adapted for the wear simulation of prosthetic hip joints. Each station had a unique motion, characterized by the so-called slide track, the track of the pin on the disk. The slide track shapes included 10 ellipses, their aspect ratio (AR) varying from 1.1 to 11.0, and a circle and a straight line as extreme cases. Hence for the first time in hip wear simulation, the motion was systematically varied over a wide range. Conventional UHMWPE pins were tested against polished CoCr disks in diluted calf serum three times for 3 million cycles. Below the AR value of 5.5, the polyethylene wear factor and wear mechanisms agreed with clinical observations. Above this value, the wear factor decreased to unrealistically low values, and the wear surface topography differed from that of retrieved acetabular cups. The wear particles, however, were similar to those isolated from periprosthetic tissues, irrespective of the AR value. In conclusion, it is recommended that the AR value be kept well below the critical point of 5.5.

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“…In earlier studies, Saikko and Calonius presented the first verified computations of the kinematics of the prosthetic hip joint illustrated as so-called slide track patterns [1][2][3][4].…”

Section: Introductionmentioning

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

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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.

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Slide track analysis of eight contemporary hip simulator designs

Cited by 54 publications

References 13 publications

Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup

Effect of increased load on the wear of a large diameter metal-on-metal modular hip prosthesis with a high inclination angle of the acetabular cup

Effect of slide track shape on the wear of ultra‐high molecular weight polyethylene in a pin‐on‐disk wear simulation of total hip prosthesis

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

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