a Departamento de Ortopedia, Santa Casa de São Paulo, São Paulo, SP, Brasil
b Serviço de Ortopedia e Traumatologia, Hospital Israelita Albert Einstein, Universidade Federal de São Paulo (Unifesp), São Paulo, SP,Brasil
c Instituto de Ortopedia, Hospital das Clínicas, Faculdade de Medicina, Universidade de São Paulo (USP), São Paulo, SP, Brasil
d Escola Paulista de Medicina, Universidade Federal de São Paulo (Unifesp), São Paulo, SP, Brasil
Introduction
Objective: To evaluate the reproducibility of the radiographic classifications of Gartland andthe Association for Osteosynthesis/Association for the Study of Internal Fixation (AO/ASIF)for supracondylar fractures of the humerus in children.Methods: On two occasions, 50 radiographs in anteroposterior and lateral views were evalu-ated by three pediatric orthopedists in accordance with the Gartland and AO/ASIF pediatricclassifications. Their responses were subjected to statistical analysis consisting of cal-culation of the coefficient to assess the intra- and interobserver concordance, in bothclassifications.Results: The strength of the intraobserver concordance was high or near perfect for the threeexaminers in the two classification systems. The strength of the interobserver concordancewas high in the two systems, with coefficients of 0.756 for the Gartland classification and0.766 for the AO/ASIF classification.Conclusion: The Gartland and AO/ASIF classification systems showed similar reproducibilityand performance. High strength of concordance was seen in the intra- and interobserveranalyses.
Supracondylar fractures are the commonest type of elbowfractures in children and the second commonest type of frac-ture during childhood, accounting for more than 60% of thecases.1-4They occur most frequently between the ages of fiveand ten years.5The various classification systems proposedfor these fractures have had the aims of guiding the treat-ment, estimating the prognosis and enabling standardizationand comparison among the many scientific studies. Theseclassifications need to be simple, easy to apply clinically andreproducible, with high concordance between surgeons.6-8The Gartland classification for supracondylar fractures of thehumerus is the one most used.9,10In this classification system,fractures are grouped according to their degree of displace-ment.
Although the LaGrange11classification is more descriptiveand detailed in cases of greater displacement, it is not thesystem most used.
In turn, the system adopted by the AO group12for fracturesof the long bones in children combines the classification ofMuller et al.13for adults with an additional description focusedon the immature skeleton.8This is an alphanumeric systemthat includes the bone affected, the location and the sever-ity, along with the peculiarities of the growing bone. Thus,supracondylar fractures would be described as 13-/9.1 with anending of I, II, III or IV, according to whether the fracture wascomplete or incomplete, and with or without contact betweenthe fragments. In this manner, only the exception component(I-IV) of the morphological segment of the AO/ASIF classifica-tion was taken into consideration in the present study.
The objective of this study was to assess the reproducibilityof the Gartland and AO/ASIF classifications for supracondy-lar fractures of the humerus in children, by investigating thelevels of intra- and interobserver concordance.
Methods
This study was conducted in a referral hospital that attendsorthopedic trauma cases, after receiving approval from theinstitution's ethics committee. Fifty conventional radiographs (anteroposterior and lateral views) originating from initialattendance of patients with supracondylar fractures of thehumerus, produced between January and June 2013, wereselected for evaluation.
The radiographic images for the study were obtained bymeans of high-resolution digital photography, with preserva-tion of the original characteristics of the film.
The selection did not take into consideration the qualityof the radiography. Images from patients over the age of 16years, from those who presented a closed growth plate lineand from those presenting multiple fractures on radiographswere excluded. The images were evaluated by three pediatricorthopedists who had had previous access to the classifica-tion systems. Seven days of training before the analysis waspermitted.
The examiners evaluated the 50 images over a maximumtime of two hours and made a second evaluation with thesame duration, two weeks later. The order of the 50 imageswas varied through randomization. The examiners did nothave access to the responses of their peers or to their ownresponses given on the previous occasion.
The responses given by each examiner to the radiographicevaluations were written on a printed chart that was handedout to each participant, together with a free and informedconsent statement.
The results were gathered and analyzed with the aid ofthe SPSS®software, version 12.0 (Chicago, USA), in order todetermine the coefficient, which inferred the degree of con-cordance beyond what would be expected only by chance. Thestrength of the intra- and interobserver concordance of the
two classification systems was then determined, as detainedin Table 1.
Results
The intraobserver concordance according to the coeffi-cient, relating to the Gartland classification for supracondylarfractures of the humerus in children and the AO/ASIF clas-sification for fractures in children, as presented in Table 2,was high or almost perfect for all the examiners in relationto both classifications. For two of the three examiners, theconcordance for the AO/ASIF system was slightly higher.
Tables 3 and 4 present the interobserver analyses for theGartland and AO classifications, respectively. It can be seenthat the interobserver concordance decreased with regard tocategory II, in both classification systems.
As shown in Table 5, the interobserver evaluation showed of 0.756 for the Gartland classification and 0.766 for theAO/ASIF classification, which thus shows high concordancebetween the two systems.
Discussion
The diversity of classification systems for a group of fracturesthat is published over the course of time may give rise to inter-pretational conflicts.
Thus, the validity, reproducibility and correlations of well-established classifications need to be verified, given thatcomparisons between different evaluations, with exclusion ofcausality and personal bias, can demonstrate the qualities orweaknesses of a given system under examination. Accordingto Audigé et al.,6for these objective to be attained, the clas-sification system needs to go through three research phasesbefore it is validated for clinical use.
To know whether a given characterization or classificationfor an object is reliable, this object needs to be evaluated sev-eral times, by more than one examiner. For this, in the presentstudy, the coefficient was used. This infers the degree of con-cordance beyond what would be expected purely by chance.It is based on the number of concordant responses, i.e. thenumber of cases for which the result is the same among theexaminers.
In the present study, the examiners seemed to be "wellcalibrated", both within themselves and with the others. Theinterobserver concordance values were within the 95% con-fidence interval, with p < 0.001 in both classification systems.Therefore, these values presented statistical significance. Asalso found by Brandão et al.,14our interobserver concordanceindex was no greater than 0.8, even though the observers wereall pediatric orthopedists.
The concordance found between the Gartland and AO/ASIFclassification systems was satisfactory (high or almost per-fect). These systems had similar performance, despite thegreater complexity of the AO/ASIF system and the examiners'lower degree of familiarity with this system.
In the present study, the lowest strength of concordance(moderate) in the interobserver analysis was found in type II ofthe Gartland and AO/ASIF classifications. However, accordingto Heal et al.,10the lowest level of interobserver concordancefor the Gartland classification occurred in type I.
It was observed that variations in the degree of concord-ance in the interobserver analysis of different studies10,14did
not invalidate the constant observation that the two classifi-cations have good reproducibility.
Evaluation of the reproducibility of these classifications isof importance insofar as they guide the type of treatment insti-tuted for these fractures (conservative versus surgical). Theyalso enable standardization of the orthopedic language forcomparing studies from different centers.
Now that the reproducibility of these classification systemshas been verified, it becomes necessary to conduct furtherstudies to ascertain whether one of them might be superiorto the other and thus to determine a standard system.
Conclusion
The Gartland and AO/ASIF classification systems showed sim-ilar reproducibility and the intra- and interobserver analysesshowed high strength of concordance, even though use ofthe AO/ASIF system remains limited among orthopedists and,consequently, their familiarity with this method is lower.
Conflicts of interest
The authors declare no conflicts of interest.
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