Observational Study
Copyright ©The Author(s) 2019. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Orthop. Jan 18, 2019; 10(1): 14-22
Published online Jan 18, 2019. doi: 10.5312/wjo.v10.i1.14
Inter- and intra-rater reliability of vertebral fracture classifications in the Swedish fracture register
David Morgonsköld, Victoria Warkander, Panayiotis Savvides, Axel Wihlborg, Mathilde Bouzereau, Hans Möller, Paul Gerdhem
David Morgonsköld, Panayiotis Savvides, Axel Wihlborg, Hans Möller, Paul Gerdhem, Department of Clinical Science, Intervention and Technology, Karolinska Institutet, Stockholm SE-14186, Sweden
Victoria Warkander, Department of Orthopaedics, Danderyd Hospital, Danderyd 18288, Sweden
Panayiotis Savvides, Axel Wihlborg, Hans Möller, Paul Gerdhem, Department of Orthopaedics, Karolinska University Hospital, Stockholm SE-14186, Sweden
Mathilde Bouzereau, Department of Emergency Medicine, Karolinska University Hospital, Stockholm SE-14186, Sweden
Author contributions: Morgonsköld D, Warkander V, Möller H and Gerdhem P designed the study. All of the authors collected the data. Morgonsköld D, Warkander V and Gerdhem P made the analysis and manuscript draft. Savvides P, Wihlborg A, Bouzereau M, Möller H and Gerdhem P made the manuscript comment. Morgonsköld D and Gerdhem P finalized the manuscript.
Institutional review board statement: The regional Ethical Review Board in Stockholm, Sweden, approved the study, No. 2016/897-31/1. All patients were investigated and treated according to clinical guidelines. No interventions were made.
Informed consent statement: Patient consent was not required for the retrieval of radiological images from the hospital. Verbal consent was obtained from the physicians that classified the images.
Conflict-of-interest statement: None of the authors has any conflicting interests.
Data sharing statement: Data can be provided on request by the corresponding author.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Corresponding author: Paul Gerdhem, MD, PhD, Associate Professor, Department of Orthopaedics, Karolinska University Hospital, K54, Huddinge, Stockholm SE-14186, Sweden. paul.gerdhem@sll.se
Telephone: +46-58-580000
Received: September 12, 2018
Peer-review started: September 12, 2018
First decision: October 15, 2018
Revised: October 27, 2018
Accepted: December 24, 2018
Article in press: December 24, 2018
Published online: January 18, 2019
Research background

The Swedish Fracture register gives the possibility to attain nationwide data on fractures.

Research motivation

Classification of vertebral fractures have recently been introduced in the register.

Research objectives

We tested the inter- and intra-rater reliability of the vertebral fracture classifications in the Swedish Fracture register.

Research methods

Radiological images of consecutive patients with vertebral fractures were classified by 5 raters with different experience levels at two occasions.

Research results

The mean kappa coefficient for inter-rater reliability ranged between 0.51 and 0.79 for the different classifications (overall and for different sub classifications). The mean kappa coefficient for intra-rater reliability ranged between 0.46 and 0.81.

Research conclusions

The classifications have an acceptable inter- and intra-rater reliability with a moderate strength of agreement.

Research perspectives

The results indicate that the Swedish Fracture register is ready for use in epidemiological studies. Studies comparing treatment outcome should consider reclassifying images to ensure correct classification.