Reproducibility and Diagnostic Accuracy of Kellgren-Lawrence Grading for Osteoarthritis Using Radiographs and Dual-Energy X-ray Absorptiometry Images

Kanako Yoshida, Rebecca J Barr, Sandro Galea-Soler, Richard M Aspden, David M Reid, Jennifer S Gregory

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Advances in image quality from modern dual-energy X-ray absorptiometry (DXA) scanners now allow near radiograph-like quality images at a low radiation dose. This opens potential new applications for the use of DXA scanners to study other musculoskeletal conditions, such as osteoarthritis, which is often investigated by visual assessment of radiographs. Together, osteoporosis and osteoarthritis are the 2 most common musculoskeletal conditions, both of which primarily affect older people. The aim of this study was to determine whether Kellgren-Lawrence grading of DXA images can be used to grade hip osteoarthritis as effectively as radiographs. People who had attended for recent pelvic radiographs underwent DXA of hips (50 hips from 25 people) using a GE Healthcare iDXA scanner. Three observers assigned Kellgren-Lawrence grades to each image, and grading was repeated at least 1 week apart. Intraobserver and interobserver reliability for radiographs and DXA images were calculated using quadratic-weighted kappa (QWK). People were recalled 12 months later, and the tests were repeated with both the radiograph and DXA scans taken within 2 weeks of each other. Hip DXA intraobserver reproducibility achieved a QWK range of 0.88-0.95 and interobserver reproducibility of 0.85-0.88, similar to QWK from hip radiographs. Intraobserver reliability between subject-matched radiograph and iDXA images revealed QWK ranging between 0.80 and 0.88. Reproducibility of hip osteoarthritis grading using DXA was comparable with that of radiographs in this study and similar to repeatability scores previously published in literature. Given the lower radiation dose and the opportunity to simultaneously investigate osteoporosis, DXA presents an attractive imaging option for osteoarthritis.

Original languageEnglish
Pages (from-to)239-244
Number of pages6
JournalJournal of Clinical Densitometry
Issue number2
Early online date8 Oct 2014
Publication statusPublished - Apr 2015

Bibliographical note

Copyright © 2014 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

The authors would like to thank all the study volunteers, radiographers Lana Gibson and Jennifer Scott as well as Carol McKerron for administrative support. The acquisition of scans was supported in part by an award (Ref: WHMSB_AU_068_071) from the Translational Medicine Research Initiative - a consortium made up of the Universities of Aberdeen, Dundee, Edinburgh and Glasgow, the four associated NHS Health Boards (Grampian, Tayside, Lothian and Greater Glasgow & Clyde), Scottish Enterprise and Pfizer. Kanako Yoshida is funded by the Grampian Osteoporosis Trust (GOT). Jennifer Gregory is supported by the Medical Research Council [G0901242].


  • bone mineral density
  • DXA
  • Kellgren-Lawrence
  • osteoarthritis
  • osteoperosis


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