Document Detail


Polyethylene wear in unicondylar knee prostheses. 106 retrieved Marmor, PCA, and St Georg tibial components compared.
MedLine Citation:
PMID:  1609584     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
106 unicondylar knee replacement tibial components were retrieved and analyzed for the amount and type of polyethylene wear. Three different designs were retrieved which had essentially the same femorotibial conformity. Each design showed a characteristic failure pattern. The polyethylene of PCA tibial components showed serious delamination after only short durations, as a result of heat pressing. St Georg sledge prostheses showed some delamination after 4 years' duration due to sub-surface cracks which were initiated by fusion defects in the polyethylene; metal backing of the components did not affect delamination of this prosthesis. The Marmor designs showed the least wear, with shiny depressions and surface pitting; no delamination was observed in the Marmor prosthesis. Molecular weight determination by gel permeation chromatography and analysis of crystallinity using Fourier transformation infra-red spectroscopy demonstrated that St George polyethylene had higher molecular weight and crystallinity than Marmor polyethylene. In some of the components investigated, crystallinity and molecular weight of the polyethylene were reduced under the wear track when compared with the unworn polyethylene. Since fusion defects may cause delamination of polyethylene we urge manufacturers to reduce the number of such defects.
Authors:
G W Blunn; A B Joshi; P A Lilley; E Engelbrecht; L Ryd; L Lidgren; K Hardinge; E Nieder; P S Walker
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Acta orthopaedica Scandinavica     Volume:  63     ISSN:  0001-6470     ISO Abbreviation:  Acta Orthop Scand     Publication Date:  1992 Jun 
Date Detail:
Created Date:  1992-07-23     Completed Date:  1992-07-23     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0370352     Medline TA:  Acta Orthop Scand     Country:  DENMARK    
Other Details:
Languages:  eng     Pagination:  247-55     Citation Subset:  IM    
Affiliation:
Institute of Orthopedics, University College London, Stanmore, Middlesex, U.K.
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MeSH Terms
Descriptor/Qualifier:
Corrosion
Fourier Analysis
Humans
Knee Prosthesis*
Microscopy, Electron, Scanning
Molecular Weight
Polyethylenes / analysis*
Prosthesis Design
Prosthesis Failure
Spectrophotometry, Infrared / methods
Stress, Mechanical
Chemical
Reg. No./Substance:
0/Polyethylenes

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


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