Advanced

Identification of femoral head center of bipolar hemiarthroplasy in radiostereometric analysis with elementary geometrical shape models.

Tsukanaka, Masako; Röhrl, Stephan M; von Schewelov, Thord LU and Nordsletten, Lars (2016) In Journal of Biomechanics 49(3). p.469-473
Abstract
Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip stems because tantalum markers attached to the stems can be omitted. In order to create an EGS model of a femoral stem, the center of the femoral head has to be identified. The contour of the femoral head is recommended to be used. However, the contour of the femoral head cannot be detected exclusively by computer if it is combined with a bipolar head or a metal cup. We therefore hypothesized that the contour of the outer head of bipolar hemiarthroplasty can be included in the EGS model as well as the femoral head contour. We calculated the time required for the detection of the contour, the precision of analysis and the stem micromotion at 2... (More)
Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip stems because tantalum markers attached to the stems can be omitted. In order to create an EGS model of a femoral stem, the center of the femoral head has to be identified. The contour of the femoral head is recommended to be used. However, the contour of the femoral head cannot be detected exclusively by computer if it is combined with a bipolar head or a metal cup. We therefore hypothesized that the contour of the outer head of bipolar hemiarthroplasty can be included in the EGS model as well as the femoral head contour. We calculated the time required for the detection of the contour, the precision of analysis and the stem micromotion at 2 years using the two different methods in the same picture set and compared the results. The detection of the bipolar head contour was 10 times faster than that of the femoral head contour. The precision for subsidence was 0.16mm in EGS RSA with the femoral head contour, and 0.15mm with the bipolar head contour (p=0.68). The precisions were comparable and clinically acceptable. There was no significant difference between the results of the 2-year micromotion with the two different methods. We conclude that this new method is applicable to measure stem micromotion of hemi-arthoplasty with EGS RSA and the method facilitates the Radiostereometric analysis. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Journal of Biomechanics
volume
49
issue
3
pages
469 - 473
publisher
Elsevier
external identifiers
  • pmid:26705109
  • scopus:84954286656
  • wos:000371548700023
ISSN
1873-2380
DOI
10.1016/j.jbiomech.2015.11.054
language
English
LU publication?
yes
id
c9813d52-60b8-4dd0-8625-fe019b427bc2 (old id 8503519)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/26705109?dopt=Abstract
date added to LUP
2016-01-06 14:00:49
date last changed
2017-01-01 07:35:27
@article{c9813d52-60b8-4dd0-8625-fe019b427bc2,
  abstract     = {Elementary geometrical shape (EGS) models are useful in radiostereometric analysis (RSA) on hip stems because tantalum markers attached to the stems can be omitted. In order to create an EGS model of a femoral stem, the center of the femoral head has to be identified. The contour of the femoral head is recommended to be used. However, the contour of the femoral head cannot be detected exclusively by computer if it is combined with a bipolar head or a metal cup. We therefore hypothesized that the contour of the outer head of bipolar hemiarthroplasty can be included in the EGS model as well as the femoral head contour. We calculated the time required for the detection of the contour, the precision of analysis and the stem micromotion at 2 years using the two different methods in the same picture set and compared the results. The detection of the bipolar head contour was 10 times faster than that of the femoral head contour. The precision for subsidence was 0.16mm in EGS RSA with the femoral head contour, and 0.15mm with the bipolar head contour (p=0.68). The precisions were comparable and clinically acceptable. There was no significant difference between the results of the 2-year micromotion with the two different methods. We conclude that this new method is applicable to measure stem micromotion of hemi-arthoplasty with EGS RSA and the method facilitates the Radiostereometric analysis.},
  author       = {Tsukanaka, Masako and Röhrl, Stephan M and von Schewelov, Thord and Nordsletten, Lars},
  issn         = {1873-2380},
  language     = {eng},
  number       = {3},
  pages        = {469--473},
  publisher    = {Elsevier},
  series       = {Journal of Biomechanics},
  title        = {Identification of femoral head center of bipolar hemiarthroplasy in radiostereometric analysis with elementary geometrical shape models.},
  url          = {http://dx.doi.org/10.1016/j.jbiomech.2015.11.054},
  volume       = {49},
  year         = {2016},
}