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A New Method to Make 2-D Wear Measurements Less Sensitive to Projection Differences of Cemented THAs

The, Bertram; Flivik, Gunnar LU ; Diercks, Ron L and Verdonschot, Nico (2008) In Clinical Orthopaedics and Related Research 466(3). p.684-690
Abstract
Wear curves from individual patients often show unexplained irregular wear curves or impossible values (negative wear). We postulated errors of two-dimensional wear measurements are mainly the result of radiographic projection differences. We tested a new method that makes two-dimensional wear measurements less sensitive for radiograph projection differences of cemented THAs. The measurement errors that occur when radiographically projecting a three-dimensional THA were modeled. Based on the model, we developed a method to reduce the errors, thus approximating three-dimensional linear wear values, which are less sensitive for projection differences. An error analysis was performed by virtually simulating 144 wear measurements under varying... (More)
Wear curves from individual patients often show unexplained irregular wear curves or impossible values (negative wear). We postulated errors of two-dimensional wear measurements are mainly the result of radiographic projection differences. We tested a new method that makes two-dimensional wear measurements less sensitive for radiograph projection differences of cemented THAs. The measurement errors that occur when radiographically projecting a three-dimensional THA were modeled. Based on the model, we developed a method to reduce the errors, thus approximating three-dimensional linear wear values, which are less sensitive for projection differences. An error analysis was performed by virtually simulating 144 wear measurements under varying conditions with and without application of the correction: the mean absolute error was reduced from 1.8 mm (range, 0-4.51 mm) to 0.11 mm (range, 0-0.27 mm). For clinical validation, radiostereometric analysis was performed on 47 patients to determine the true wear at 1, 2, and 5 years. Subsequently, wear was measured on conventional radiographs with and without the correction: the overall occurrence of errors greater than 0.2 mm was reduced from 35% to 15%. Wear measurements are less sensitive to differences in two-dimensional projection of the THA when using the correction method. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Clinical Orthopaedics and Related Research
volume
466
issue
3
pages
684 - 690
publisher
Lippincott Williams & Wilkins
external identifiers
  • pmid:18264857
  • wos:000253492700025
  • scopus:42449131827
ISSN
0009-921X
DOI
10.1007/s11999-007-0077-3
language
English
LU publication?
yes
id
1cfde849-c03f-48ad-ab8f-1a718a94dabc (old id 1144696)
date added to LUP
2008-08-15 08:47:29
date last changed
2017-01-01 04:55:41
@article{1cfde849-c03f-48ad-ab8f-1a718a94dabc,
  abstract     = {Wear curves from individual patients often show unexplained irregular wear curves or impossible values (negative wear). We postulated errors of two-dimensional wear measurements are mainly the result of radiographic projection differences. We tested a new method that makes two-dimensional wear measurements less sensitive for radiograph projection differences of cemented THAs. The measurement errors that occur when radiographically projecting a three-dimensional THA were modeled. Based on the model, we developed a method to reduce the errors, thus approximating three-dimensional linear wear values, which are less sensitive for projection differences. An error analysis was performed by virtually simulating 144 wear measurements under varying conditions with and without application of the correction: the mean absolute error was reduced from 1.8 mm (range, 0-4.51 mm) to 0.11 mm (range, 0-0.27 mm). For clinical validation, radiostereometric analysis was performed on 47 patients to determine the true wear at 1, 2, and 5 years. Subsequently, wear was measured on conventional radiographs with and without the correction: the overall occurrence of errors greater than 0.2 mm was reduced from 35% to 15%. Wear measurements are less sensitive to differences in two-dimensional projection of the THA when using the correction method.},
  author       = {The, Bertram and Flivik, Gunnar and Diercks, Ron L and Verdonschot, Nico},
  issn         = {0009-921X},
  language     = {eng},
  number       = {3},
  pages        = {684--690},
  publisher    = {Lippincott Williams & Wilkins},
  series       = {Clinical Orthopaedics and Related Research},
  title        = {A New Method to Make 2-D Wear Measurements Less Sensitive to Projection Differences of Cemented THAs},
  url          = {http://dx.doi.org/10.1007/s11999-007-0077-3},
  volume       = {466},
  year         = {2008},
}