Test-retest, inter- and intra-rater reliability of the flexicurve for evaluation of the spine in children

INTRODUCTION: The early evaluation of the spine in children is desirable because it is at this stage of development that the greatest changes in the body structures occur. OBJECTIVE: To determine the test-retest, intra- and inter-rater reliability of the Flexicurve instrument for the evaluation of spinal curvatures in children. METHOD: Forty children ranging from 5 to 15 years of age were evaluated by two independent evaluators using the Flexicurve to model the spine. The agreement was evaluated using Intraclass Correlation Coefficients (ICC), Standard Error of the Measurement (SEM), and Minimal Detectable Change (MDC). RESULTS: In relation to thoracic kyphosis, the Flexicurve was shown to have excellent correlation in terms of test-retest reliability (ICC(2,2)=0.87) and moderate correlation in terms of intra-(ICC(2,2)=0.68) and inter-rater reliability (ICC(2,2)=0.72). In relation to lumbar lordosis, it was shown to have moderate correlation in terms of test-retest reliability (ICC(2,2)=0.66) and intra- (ICC(2,2)=0.50) and inter-rater reliability (ICC=0.56). CONCLUSION: This evaluation of the reliability of the Flexicurve allows its use in school screening. However, to monitor spinal curvatures in the sagittal plane in children, complementary clinical measures are necessary. Further studies are required to investigate the concurrent validity of the instrument in order to identify its diagnostic capacity.