Diagnostic Methods: Comparative StudyEvaluation of knee range of motion: Correlation between measurements using a universal goniometer and a smartphone goniometric application

BackgroundGoniometers are commonly used to measure range of motion in the musculoskeletal system. Recently smartphone goniometry applications have become available to clinicians.ObjectiveCompare angular measures using a universal goniometer and a smartphone application.MethodsThirty four healthy women with at least 20° of limited range of motion regarding knee extension were recruited. Knee flexion angles of the dominant limb were measured with a universal goniometer and the ROM© goniometric application for the smartphone. Three trained examiners compared the two assessment tools.ResultsStrong correlations were found between the measures of the universal goniometer and smartphone application (Pearson's correlation and interclass correlation coefficient > 0.93). The measurements with both devices demonstrated low dispersion and little variation.ConclusionMeasurements obtained using the smartphone goniometric application analyzed are as reliable as those of a universal goniometer. This application is therefore a useful tool for the evaluation of knee range of motion.