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Distances and angles in standing long-leg radiographs: comparing conventional radiography, digital radiography, and EOS.

Distances and angles in standing long-leg radiographs: comparing conventional radiography, digital radiography, and EOS.

Authors :
Birkenmaier, Christof
Levrard, Louise
Melcher, Carolin
Wegener, Bernd
Ricke, Jens
Holzapfel, Boris M.
Baur-Melnyk, Andrea
Mehrens, Dirk
Source :
Skeletal Radiology; Aug2024, Vol. 53 Issue 8, p1517-1528, 12p
Publication Year :
2024

Abstract

Objective: Distances and angles measured from long-leg radiographs (LLR) are important for surgical decision-making. However, projectional radiography suffers from distortion, potentially generating differences between measurement and true anatomical dimension. These phenomena are not uniform between conventional radiography (CR) digital radiography (DR) and fan-beam technology (EOS). We aimed to identify differences between these modalities in an experimental setup. Materials and methods: A hemiskeleton was stabilized using an external fixator in neutral, valgus and varus knee alignment. Ten images were acquired for each alignment and each modality: one CR setup, two different DR systems, and an EOS. A total of 1680 measurements were acquired and analyzed. Results: We observed great differences for dimensions and angles between the 4 modalities. Femoral head diameter measurements varied in the range of > 5 mm depending on the modality, with EOS being the closest to the true anatomical dimension. With functional leg length, a difference of 8.7% was observed between CR and EOS and with the EOS system being precise in the vertical dimension on physical-technical grounds, this demonstrates significant projectional magnification with CR-LLR. The horizontal distance between the medial malleoli varied by 20 mm between CR and DR, equating to 21% of the mean. Conclusions: Projectional distortion resulting in variations approaching 21% of the mean indicate, that our confidence on measurements from standing LLR may not be justified. It appears likely that among the tested equipment, EOS-generated images are closest to the true anatomical situation most of the time. [ABSTRACT FROM AUTHOR]

Details

Language :
English
ISSN :
03642348
Volume :
53
Issue :
8
Database :
Complementary Index
Journal :
Skeletal Radiology
Publication Type :
Academic Journal
Accession number :
178029223
Full Text :
https://doi.org/10.1007/s00256-024-04592-9