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Accuracy of radiographic and radiostereometric wear measurement of different hip prostheses: an experimental study.

von Schewelov, Thord LU ; Sanzén, Lennart; Börlin, Niclas; Markusson, Patrik LU and Önsten, Ingemar LU (2004) In Acta Orthopaedica Scandinavica 75(6). p.691-700
Abstract
Background In vivo measurement of wear in the ball and socket articulation of total hip arthroplasties is of interest in the evaluation of both existing and new implants. Controversy reigns regarding the accuracy of different radiological measurement techniques and in particular how accuracy has been assessed.



Material and methods We assessed the accuracy of 2 radiostereometric (RSA) techniques for wear measurement and 3 standard radiographic techniques, namely Imagika (image analyzing software), Imagika corrected for head center displacement, and the Charnley Duo method. 5 custom-made adjustable phantoms with different prosthetic components were used.



Results In 20 measurements of all 5 phantoms at 3... (More)
Background In vivo measurement of wear in the ball and socket articulation of total hip arthroplasties is of interest in the evaluation of both existing and new implants. Controversy reigns regarding the accuracy of different radiological measurement techniques and in particular how accuracy has been assessed.



Material and methods We assessed the accuracy of 2 radiostereometric (RSA) techniques for wear measurement and 3 standard radiographic techniques, namely Imagika (image analyzing software), Imagika corrected for head center displacement, and the Charnley Duo method. 5 custom-made adjustable phantoms with different prosthetic components were used.



Results In 20 measurements of all 5 phantoms at 3 levels of simulated wear (0.2 mm, 1.0 mm and 1.5 mm), the mean measurement error of the digital RSA examinations was 0.010 mm (accuracy 0.42). The corresponding error values for the three radiographic techniques were 0.19 (accuracy 1.3) for Charnley Duo, 0.13 (accuracy 1.3) for Imagika corrected, and 1.021 (accuracy 2.99) for Imagika. Measurement error decreased from 0.011 mm with ordinary RSA to 0.004 with RSA digital measurement. Head size, direction of wear in relation to the cup or type of prosthetic component did not influence the measurement error. The results of Charnley Duo and Imagika corrected were similar but the latter had an inexplicable systematic error in measuring one of the phantoms. Imagika had the worst results due to its inability to compensate for the out-of-head center effect. Alumina heads were difficult to analyze with all methods.



Interpretation By using the ISO standard for assessing accuracy, RSA can be expected to measure wear with an accuracy of about 0.4 mm irrespective of prosthetic component studied or direction of wear, whereas the best technique, in our study, based on standard radiographs can be accurate to about 1.3 mm. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Imaging, Prosthesis Failure, Hip Prosthesis, Phantoms, Comparative Study, Hip, Replacement, Arthroplasty
in
Acta Orthopaedica Scandinavica
volume
75
issue
6
pages
691 - 700
publisher
Taylor & Francis
external identifiers
  • wos:000226050700006
  • pmid:15762258
  • scopus:10944233565
ISSN
0001-6470
DOI
10.1080/00016470410004058
language
English
LU publication?
yes
id
abf9089b-f1a5-4b91-bb39-2f544ae84546 (old id 135022)
alternative location
http://www.ncbi.nlm.nih.gov/sites/entrez?cmd=Retrieve&db=PubMed&list_uids=15762258&dopt=AbstractPlus
date added to LUP
2007-07-30 12:06:20
date last changed
2017-11-27 12:52:55
@article{abf9089b-f1a5-4b91-bb39-2f544ae84546,
  abstract     = {Background In vivo measurement of wear in the ball and socket articulation of total hip arthroplasties is of interest in the evaluation of both existing and new implants. Controversy reigns regarding the accuracy of different radiological measurement techniques and in particular how accuracy has been assessed.<br/><br>
<br/><br>
Material and methods We assessed the accuracy of 2 radiostereometric (RSA) techniques for wear measurement and 3 standard radiographic techniques, namely Imagika (image analyzing software), Imagika corrected for head center displacement, and the Charnley Duo method. 5 custom-made adjustable phantoms with different prosthetic components were used.<br/><br>
<br/><br>
Results In 20 measurements of all 5 phantoms at 3 levels of simulated wear (0.2 mm, 1.0 mm and 1.5 mm), the mean measurement error of the digital RSA examinations was 0.010 mm (accuracy 0.42). The corresponding error values for the three radiographic techniques were 0.19 (accuracy 1.3) for Charnley Duo, 0.13 (accuracy 1.3) for Imagika corrected, and 1.021 (accuracy 2.99) for Imagika. Measurement error decreased from 0.011 mm with ordinary RSA to 0.004 with RSA digital measurement. Head size, direction of wear in relation to the cup or type of prosthetic component did not influence the measurement error. The results of Charnley Duo and Imagika corrected were similar but the latter had an inexplicable systematic error in measuring one of the phantoms. Imagika had the worst results due to its inability to compensate for the out-of-head center effect. Alumina heads were difficult to analyze with all methods.<br/><br>
<br/><br>
Interpretation By using the ISO standard for assessing accuracy, RSA can be expected to measure wear with an accuracy of about 0.4 mm irrespective of prosthetic component studied or direction of wear, whereas the best technique, in our study, based on standard radiographs can be accurate to about 1.3 mm.},
  author       = {von Schewelov, Thord and Sanzén, Lennart and Börlin, Niclas and Markusson, Patrik and Önsten, Ingemar},
  issn         = {0001-6470},
  keyword      = {Imaging,Prosthesis Failure,Hip Prosthesis,Phantoms,Comparative Study,Hip,Replacement,Arthroplasty},
  language     = {eng},
  number       = {6},
  pages        = {691--700},
  publisher    = {Taylor & Francis},
  series       = {Acta Orthopaedica Scandinavica},
  title        = {Accuracy of radiographic and radiostereometric wear measurement of different hip prostheses: an experimental study.},
  url          = {http://dx.doi.org/10.1080/00016470410004058},
  volume       = {75},
  year         = {2004},
}