Document Detail

Lubrication and friction prediction in metal-on-metal hip implants.
MedLine Citation:
PMID:  18296762     Owner:  NLM     Status:  MEDLINE    
A general methodology of mixed lubrication analysis and friction prediction for a conforming spherical bearing in hip implants was developed, with particular reference to a typical metal-on-metal hip replacement. Experimental measurement of frictional torque for a similar implant was carried out to validate the theoretical prediction. A ball-in-socket configuration was adopted to represent the articulation between the femoral head and the acetabular cup under cyclic operating conditions of representative load and motion. The mixed lubrication model presented in this study was first applied to identify the contact characteristics on the bearing surfaces, consisting of both fluid-film and boundary lubricated regions. The boundary lubricated contact was assumed to occur when the predicted fluid film thickness was less than a typical boundary protein layer absorbed on the bearing surfaces. Subsequently, the friction was predicted from the fluid-film lubricated region with viscous shearing due to both Couette and Poiseuille flows and the boundary protein layer contact region with a constant coefficient of friction. The predicted frictional torque of the typical metal-on-metal hip joint implant was compared with the experimental measurement conducted in a functional hip simulator and a reasonably good agreement was found. The mixed lubrication regime was found to be dominant for the conditions considered. Although the percentage of the boundary lubricated region was quite small, the corresponding contribution to friction was quite large and the resultant friction factor was quite high.
F C Wang; C Brockett; S Williams; I Udofia; J Fisher; Z M Jin
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2008-02-13
Journal Detail:
Title:  Physics in medicine and biology     Volume:  53     ISSN:  0031-9155     ISO Abbreviation:  Phys Med Biol     Publication Date:  2008 Mar 
Date Detail:
Created Date:  2008-02-25     Completed Date:  2008-06-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0401220     Medline TA:  Phys Med Biol     Country:  England    
Other Details:
Languages:  eng     Pagination:  1277-93     Citation Subset:  IM    
Institute of Medical and Biological Engineering, School of Mechanical Engineering, University of Leeds, Leeds LS2 9JT, UK.
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MeSH Terms
Hip Joint / physiology
Models, Biological*
Prostheses and Implants*
Time Factors
Reg. No./Substance:

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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