title: Intra and interobserver concordance of the AO classification system for fractures of the long bones in the pediatric population.
abstract: OBJECTIVE
  The AO classification for fractures of the long bones in the pediatric population was developed and validated in 2006. However, the complexity of this system has limited its use in clinical practice and few studies in the literature have evaluated its reproducibility and applicability. The present study had the objective of determining the intra and interobserver agreement using the pediatric AO system, among physicians with different levels of experience.
  
  
  METHODS
  After making the sample calculation, 108 consecutive radiographs on long-bone fractures in patients aged 0-16 years, coming from the digital files of the quaternary-level hospital, were selected. The radiographs were classified by five examiners with different levels of experience after prior explanations about the system. A chart containing images from the classification was made available for consultation. The evaluations were made at two different times by each observer. The Fleiss kappa index was used to ascertain the intra and interobserver agreement.
  
  
  RESULTS
  Intraobserver agreement that was at least substantial was obtained for all the items of the classification and it reached excellent levels for all observers in relation to five of the seven items considered. The interobserver evaluation presented excellent levels of agreement in two items, substantial in two items, moderate to substantial in one item and poor to moderate in one item. No influence from the observer's experience was observed with regard to obtaining higher or lower levels of agreement, either in the intraobserver or in the interobserver evaluation.
  
  
  CONCLUSIONS
  In this study, the intra and interobserver agreement was considered to be good or excellent for the pediatric AO classification system, for the parameters of bone, segment, paired bone, subsegment, standard and deviation. However, the intra and interobserver agreement was statistically unsatisfactory for the parameter of severity/side of avulsion. The levels of agreement obtained did not depend on the observer's level of experience within pediatric orthopedics.
authors.affiliation: Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp) , São Paulo, SP, Brazil.
authors.forename: Artur Yudi
authors.initials: AY
authors.lastname: Utino
authors.affiliation: Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp) , São Paulo, SP, Brazil.
authors.forename: Douglas Rene
authors.initials: DR
authors.lastname: de Alencar
authors.affiliation: Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp) , São Paulo, SP, Brazil.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Fernadez Maringolo
authors.affiliation: Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp) , São Paulo, SP, Brazil.
authors.forename: Julia Machado
authors.initials: JM
authors.lastname: Negrão
authors.affiliation: Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp) , São Paulo, SP, Brazil.
authors.forename: Francesco Camara
authors.initials: FC
authors.lastname: Blumetti
authors.affiliation: Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp) , São Paulo, SP, Brazil.
authors.forename: Eiffel Tsuyoshi
authors.initials: ET
authors.lastname: Dobashi
keywords: Bone fractures/classification; Child; Method; Orthopedics