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  • Oral presentation
  • Open Access

The comparison and validity and reliability study of bilateral innominate vertical length measurements using innovative digital radiographic imaging software in assessing scoliotic leg length discrepancy

  • 1,
  • 2,
  • 2 and
  • 2
Scoliosis20149 (Suppl 1) :O9

  • Published:


  • Length Measurement
  • Intraclass Correlation Coefficient
  • Interobserver Reliability
  • Trained Observer
  • Intraobserver Reliability

Background information

The role of leg length discrepancy (LLD) has been implicated in certain types of scoliosis [1]. Scoliotic LLD has been suggested as a result of rotation of the innominate bones [2]. However, the role of innominate vertical lengths (IVLs) as a predisposing factor for scoliosis is not clear. The reliability of radiographic measurements may reveal whether IVL can be used as a factor for clinical assessment.


Clinical investigation of quantifying bilateral IVLs and to assess the intra- and inter-observer variability using digital radiographic techniques.


Twenty x-ray films from scoliotic patients with LLD were chosen based on convenience, without predilection for gender and age. Images were examined by 7 trained observers to compare bilateral IVLs and to estimate the variability, as well as intra- and inter-observer variations. Each image was measured 3 times at a minimum interval of 1 week. All radiographs were calibrated by the software to allow for accurate length measurements. Student’s t-test was used to compare bilateral IVLs. The intraclass correlation coefficients (ICC) were used. 95% prediction limits for the errors in measurements to determine the interobserver and intraobserver reliabilities. A mean ICC value of 0.93 was determined for interobserver reliability and a mean ICC value of 0.96 for intraobserver reliability.


Overall mean right IVL was 192.6 ± 6.94mm, and left IVL was 190.4 ± 6.95mm. Although there was a discrepancy between bilateral IVLs, there was no statistical significance (P>0.05). Interobserver ICC was 0.954 and intraobserver ICC was 0.974.


Scoliosis patients with LLD might show asymmetrical IVLs; however, this discrepancy has no statistical significance; therefore, IVL is not a strong clinical indicator in assessing scoliotic LLD. On the other hand, the computer-assisted measurements are clinically advantageous and appropriate to assess scoliosis parameters. Digital measurement among different observers showed excellent reliability for the majority of IVL parameters, making it a useful method for the analysis of pathology on radiographs in scoliosis patients.

Authors’ Affiliations

Palmer College of Chiropractic Florida, Port Orange, USA
HanSeo University, Seosan, South Korea


  1. Raczkowski JW, Daniszewska B, Zolynski K: Functional scoliosis caused by leg length discrepancy. Arch Med Sci. 2010, 6 (3): 393-398.PubMed CentralView ArticlePubMedGoogle Scholar
  2. Friberg O, Nurminen M, Korhonen K, Soininen E, Mänttäri T: Accuracy and precision of clinical estimation of leg length inequality and lumbar scoliosis: Comparison of clinical and radiological measurements. Int Disabil Stud. 1988, 10 (2): 49-53. 10.3109/09638288809164098.View ArticlePubMedGoogle Scholar


© He et al; licensee BioMed Central Ltd. 2014

This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated.