Biophotogrammetry: reliability of measurements obtained with a posture assessment software (SAPO).

Abstract

Photogrammetry is a valuable tool for the diagnosis and measurement of postural changes, but the lack of standardization of anatomical references and angular measures impairs the comparison between studies and compromises the reliability of the results. The objective of this study was to evaluate the inter- and intraexaminer reliability of angular measures proposed by the SAPO posture assessment software (v. 0.68). Twenty-four subjects were photographed in the standing position according to the recommendations of the SAPO software. Three examiners (A, B and C) experienced in the use of the software analyzed the images and repeated the analysis after 7 days. Variance, intraclass correlation coefficient (ICC), and t-test adopting a level of significance of 5% were applied. With respect to interexaminer reliability among the 20 angles measured, two were classified as unacceptable (A13: ICC = 0.623; A14: ICC = 0.568), one as acceptable (A19: ICC = 0.743), one as very good (A20: ICC = 0.860), and 16 as excellent (ICC ? 0.90). Evaluation of repeatability of the method by the same examiner showed that two angles measured by examiner A differed significantly between the two measurements (A11: p = 0.015; A12: p = 0.026), as did two angles measured by examiner B (A2: p = 0.019; A12: p = 0.015) and one angle measured by examiner C (A16, p = 0.011). In conclusion, comparison between different examiners showed that the angles proposed by the SAPO protocol are reliable for the measurement of body segments.