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Femoral Neck Hounsfield Units as an Adjunct for Bone Mineral Density After Combat-Related Lower Extremity Amputation

Hoyt, Benjamin W ; Lundy, Alex E ; Clark, DesRaj M ; Colantonio, Donald ; Tintle, Scott M LU orcid and Potter, Benjamin K (2021) In Journal of Orthopaedic Trauma 35(5). p.158-164
Abstract

OBJECTIVES: To correlate femoral neck Hounsfield units (HUs) measured on a computed tomography (CT) scan to dual-energy x-ray absorptiometry (DEXA) T-scores allowing evaluation of bone mineral density (BMD) over time after lower extremity trauma-related amputation.

DESIGN: Retrospective cohort study.

SETTING: United States military trauma referral center.

PATIENTS: Military combat-related lower extremity amputees with both DEXA and CT scans within 6 months of each other.

INTERVENTION: None.

MAIN OUTCOME MEASURES: Correlation between femoral neck comprehensive mean HUs and BMD and HUs threshold for low BMD.

RESULTS: Regression model correlation (r) between CT HU and DEXA T-score was r = 0.84 [95%... (More)

OBJECTIVES: To correlate femoral neck Hounsfield units (HUs) measured on a computed tomography (CT) scan to dual-energy x-ray absorptiometry (DEXA) T-scores allowing evaluation of bone mineral density (BMD) over time after lower extremity trauma-related amputation.

DESIGN: Retrospective cohort study.

SETTING: United States military trauma referral center.

PATIENTS: Military combat-related lower extremity amputees with both DEXA and CT scans within 6 months of each other.

INTERVENTION: None.

MAIN OUTCOME MEASURES: Correlation between femoral neck comprehensive mean HUs and BMD and HUs threshold for low BMD.

RESULTS: Regression model correlation (r) between CT HU and DEXA T-score was r = 0.84 [95% confidence interval (CI) 0.52-0.94] and r = 0.81 (95% CI 0.57-0.92) when CT imaging was separated from DEXA by less than 4 and 5 months, respectively. Beyond 5 months separation, correlation decreased to r = 0.60 (95% CI 0.29-0.80). Using a receiver operator characteristic curve for mean comprehensive HUs to determine low BMD with 4-month cut-off, a threshold of 151 HUs was 97% sensitive and 84% specific to identify low BMD, whereas 98 HUs was 100% sensitive and 100% specific to identify osteoporosis.

CONCLUSION: Using opportunistic CT, clinicians can reliably estimate BMD in trauma-related amputees. This information will inform providers making decisions regarding weightbearing and bisphosphonate therapy to limit further loss. Future phases of this study will aim to use this correlation to study the effects of weightbearing advancement timing, bisphosphonate therapy, and interventions on the natural history of bone density after amputation.

LEVEL OF EVIDENCE: Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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author
; ; ; ; and
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Absorptiometry, Photon, Amputation, Surgical, Bone Density, Femur Neck, Humans, Lower Extremity, Retrospective Studies
in
Journal of Orthopaedic Trauma
volume
35
issue
5
pages
158 - 164
publisher
Wolters Kluwer Health
external identifiers
  • scopus:85104275415
  • pmid:33079846
ISSN
0890-5339
DOI
10.1097/BOT.0000000000001980
language
English
LU publication?
no
additional info
Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.
id
4af26806-6304-4c04-83c7-896ea7ab6d3f
date added to LUP
2024-11-14 09:50:27
date last changed
2025-04-04 16:25:55
@article{4af26806-6304-4c04-83c7-896ea7ab6d3f,
  abstract     = {{<p>OBJECTIVES: To correlate femoral neck Hounsfield units (HUs) measured on a computed tomography (CT) scan to dual-energy x-ray absorptiometry (DEXA) T-scores allowing evaluation of bone mineral density (BMD) over time after lower extremity trauma-related amputation.</p><p>DESIGN: Retrospective cohort study.</p><p>SETTING: United States military trauma referral center.</p><p>PATIENTS: Military combat-related lower extremity amputees with both DEXA and CT scans within 6 months of each other.</p><p>INTERVENTION: None.</p><p>MAIN OUTCOME MEASURES: Correlation between femoral neck comprehensive mean HUs and BMD and HUs threshold for low BMD.</p><p>RESULTS: Regression model correlation (r) between CT HU and DEXA T-score was r = 0.84 [95% confidence interval (CI) 0.52-0.94] and r = 0.81 (95% CI 0.57-0.92) when CT imaging was separated from DEXA by less than 4 and 5 months, respectively. Beyond 5 months separation, correlation decreased to r = 0.60 (95% CI 0.29-0.80). Using a receiver operator characteristic curve for mean comprehensive HUs to determine low BMD with 4-month cut-off, a threshold of 151 HUs was 97% sensitive and 84% specific to identify low BMD, whereas 98 HUs was 100% sensitive and 100% specific to identify osteoporosis.</p><p>CONCLUSION: Using opportunistic CT, clinicians can reliably estimate BMD in trauma-related amputees. This information will inform providers making decisions regarding weightbearing and bisphosphonate therapy to limit further loss. Future phases of this study will aim to use this correlation to study the effects of weightbearing advancement timing, bisphosphonate therapy, and interventions on the natural history of bone density after amputation.</p><p>LEVEL OF EVIDENCE: Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.</p>}},
  author       = {{Hoyt, Benjamin W and Lundy, Alex E and Clark, DesRaj M and Colantonio, Donald and Tintle, Scott M and Potter, Benjamin K}},
  issn         = {{0890-5339}},
  keywords     = {{Absorptiometry, Photon; Amputation, Surgical; Bone Density; Femur Neck; Humans; Lower Extremity; Retrospective Studies}},
  language     = {{eng}},
  month        = {{05}},
  number       = {{5}},
  pages        = {{158--164}},
  publisher    = {{Wolters Kluwer Health}},
  series       = {{Journal of Orthopaedic Trauma}},
  title        = {{Femoral Neck Hounsfield Units as an Adjunct for Bone Mineral Density After Combat-Related Lower Extremity Amputation}},
  url          = {{http://dx.doi.org/10.1097/BOT.0000000000001980}},
  doi          = {{10.1097/BOT.0000000000001980}},
  volume       = {{35}},
  year         = {{2021}},
}