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Effect of hip flexion on the measurement of spinal bone mineral density in the Norland Eclipse XR

Lekamwasam, Sarath LU and Lenora, Janaka LU (2005) In Journal of Clinical Densitometry 8(2). p.183-186
Abstract
It is recommended that the hip joints be flexed to 90 degrees during dual-energy X-ray absorptiometry scanning of the lumbar spine in the anteroposterior projection; however, some patients are unable to maintain this position because of the presence of degenerative changes in lower limb joints. This study examines the effect of a lesser degree of hip flexion on the lumbar spine bone mineral density (BMD) measurement and its interpretation. Fifty women were scanned on the Norland Eclipse XR, initially in the standard position with the hips flexed to 90 degrees and then in the adjusted position after allowing for some degree of hip extension to keep them comfortable (hip flexion of 60 degrees -70 degrees ).Higher bone mineral content (BMC),... (More)
It is recommended that the hip joints be flexed to 90 degrees during dual-energy X-ray absorptiometry scanning of the lumbar spine in the anteroposterior projection; however, some patients are unable to maintain this position because of the presence of degenerative changes in lower limb joints. This study examines the effect of a lesser degree of hip flexion on the lumbar spine bone mineral density (BMD) measurement and its interpretation. Fifty women were scanned on the Norland Eclipse XR, initially in the standard position with the hips flexed to 90 degrees and then in the adjusted position after allowing for some degree of hip extension to keep them comfortable (hip flexion of 60 degrees -70 degrees ).Higher bone mineral content (BMC), surface area, and BMD values were seen in the standard position compared to the adjusted position, but none of the differences was statistically significant. There were strong correlations for BMC,surface area, and BMD measured in the two positions. In the standard position, 26 women were found to have osteoporosis and 18 had osteopenia. In the adjusted position, osteoporosis was noted in 27 women, and 18 had osteopenia.Four women showed a reduction, whereas 12 women showed an increase in BMD in excess of the least significant change at the 95% confidence level, defined as 2.77 times the precision error (0.008 g/cm(2) x 2.77 = 0.120 g/cm(2)). Our study demonstrates that a lesser degree of hip flexion in women who find it difficult to maintain the recommended 90 degrees hip flexion during the lumbar spine BMD measurement would not affect the patient classification based on T-scores recommended by the World Health Organization; however, variation in hip flexion can be a major confounding factor when interpreting a change in BMD over time. (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
patient positioning, hip flexion, lumbar spine, bone density, Osteoporosis
in
Journal of Clinical Densitometry
volume
8
issue
2
pages
183 - 186
publisher
Elsevier
external identifiers
  • pmid:15908705
  • scopus:26244441716
ISSN
1094-6950
DOI
10.1385/JCD:8:2:183
language
English
LU publication?
yes
id
2f64ff44-44a7-424d-a61c-a56d2d474623 (old id 1133095)
alternative location
http://www.sciencedirect.com.ludwig.lub.lu.se/science/article/pii/S1094695006600383
http://www.ncbi.nlm.nih.gov/pubmed/15908705
date added to LUP
2013-10-16 15:16:57
date last changed
2017-10-08 03:42:56
@article{2f64ff44-44a7-424d-a61c-a56d2d474623,
  abstract     = {It is recommended that the hip joints be flexed to 90 degrees during dual-energy X-ray absorptiometry scanning of the lumbar spine in the anteroposterior projection; however, some patients are unable to maintain this position because of the presence of degenerative changes in lower limb joints. This study examines the effect of a lesser degree of hip flexion on the lumbar spine bone mineral density (BMD) measurement and its interpretation. Fifty women were scanned on the Norland Eclipse XR, initially in the standard position with the hips flexed to 90 degrees and then in the adjusted position after allowing for some degree of hip extension to keep them comfortable (hip flexion of 60 degrees -70 degrees ).Higher bone mineral content (BMC), surface area, and BMD values were seen in the standard position compared to the adjusted position, but none of the differences was statistically significant. There were strong correlations for BMC,surface area, and BMD measured in the two positions. In the standard position, 26 women were found to have osteoporosis and 18 had osteopenia. In the adjusted position, osteoporosis was noted in 27 women, and 18 had osteopenia.Four women showed a reduction, whereas 12 women showed an increase in BMD in excess of the least significant change at the 95% confidence level, defined as 2.77 times the precision error (0.008 g/cm(2) x 2.77 = 0.120 g/cm(2)). Our study demonstrates that a lesser degree of hip flexion in women who find it difficult to maintain the recommended 90 degrees hip flexion during the lumbar spine BMD measurement would not affect the patient classification based on T-scores recommended by the World Health Organization; however, variation in hip flexion can be a major confounding factor when interpreting a change in BMD over time.},
  author       = {Lekamwasam, Sarath and Lenora, Janaka},
  issn         = {1094-6950},
  keyword      = {patient positioning,hip flexion,lumbar spine,bone density,Osteoporosis},
  language     = {eng},
  number       = {2},
  pages        = {183--186},
  publisher    = {Elsevier},
  series       = {Journal of Clinical Densitometry},
  title        = {Effect of hip flexion on the measurement of spinal bone mineral density in the Norland Eclipse XR},
  url          = {http://dx.doi.org/10.1385/JCD:8:2:183},
  volume       = {8},
  year         = {2005},
}