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  • Oral presentation
  • Open Access

The reliability and prognostic implications of a simplified bone age classification system for adolescent idiopathic scoliosis

  • 1,
  • 1,
  • 2 and
  • 1
Scoliosis20127 (Suppl 1) :O14

  • Published:


  • Public Health
  • Treatment Decision
  • Classification System
  • Multicenter Trial
  • Adolescent Idiopathic Scoliosis


Sanders et al. [1, 2] describe a simplified system for determining digital skeletal age (DSA) and its use in predicting the likelihood a curve will reach surgical magnitude. We assessed the inter-and intra-rater reliability and prognostic implications of this classification system using data from a multicenter trial of outcomes in AIS (BrAIST).

Material and methods

36 subjects were randomly selected. We determined the predicted prognosis by cross-classifying the DSA and Cobb angle using Sanders’ estimates.


Kappa coefficients ranged from 0.76 to 0.88. For example, one rater’s reading corresponded to a 0% risk of the curve reaching surgical magnitude, while the other rater’s reading for the same subject corresponded to a 92% risk.

The high level of agreement in DSA found by Sanders et. al was replicated in this study, and would be considered “substantial” to “almost perfect” using widely applied standards [3] Despite this agreement, different prognoses were predicted for 11% of these subjects.


Clinicians and researchers should consider seeking a second review of the DSA (especially if it appears to be in the DSA 2 to 3 range), and the Cobb angle, prior to using it to make prognostic predictions and treatment decisions.

Authors’ Affiliations

University of Iowa, Department of Orthopaedic Surgery, Iowa City, IA 52242-1007, USA
University of Iowa, Department of Radiology, Iowa City, USA


  1. Sanders JO, Browne RH, McConnell SJ: Maturity assessment and curve progression in girls with Idiopathic Scoliosis. J Bone Joint Surg Am. 2007, 89: 64-73.View ArticlePubMedGoogle Scholar
  2. Sanders JO, Khoury JG, Kishan S, Browne RH, Mooney JF, Arnold KD, McConnell SJ, Bauman JA, Finegold DN: Predicting scoliosis progression from skeletal maturity: a simplified classification during adolescence. J Bone Joint Surg Am. 2008, 90 (3): 540-53. 10.2106/JBJS.G.00004.View ArticlePubMedGoogle Scholar
  3. Landis JR, Koch GG: The measurement of observer agreement for categorical data. Biometrics. 1977, 33: 159-74. 10.2307/2529310.View ArticlePubMedGoogle Scholar


© Dolan et al; licensee BioMed Central Ltd. 2012

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.