Reliability and validity of goniometric and photographic measurements of clavicular tilt angle

The aims of the present study were to assess the reliability of clavicular tilt angle measurement using goniometric and photographic measurements and to test the validity of the measurement by comparing the results with radiographic findings (gold standard).Clavicular tilt angles were measured in 18 healthy subjects (36 clavicles) using goniometric, photographic, and radiographic measurement. Repeated measurements using goniometric and photographic measurements were made in two test sessions conducted on different days by two examiners to assess inter-rater and intra-rater reliability of the two methods. Radiographic measurement was taken once, and the correlation between the radiographic findings and those of the indirect methods was calculated to test the validity of the goniometric and photographic measurement of clavicular tilt angle.No significant difference in clavicular tilt angle measurement was found between test sessions. The reliability of goniometric measurement (inter-rater intraclass correlation coefficients (ICC) = 0.85 (95% CI = 0.72–0.92) − 0.87 (95% CI = 0.77–0.87); intra-rater ICC = 0.80 (95% CI = 0.64–0.89)) and photographic measurement (inter-rater ICC = 0.89 (95% CI = 0.80–0.94) − 0.95 (95% CI = 0.91–0.98); intra-rater ICC = 0.84 (95% CI = 0.71–0.92) − 0.84 (95% CI = 0.69–0.91)) were excellent. The goniometric and photographic measurements of clavicular tilt angle were highly correlated with the radiographic findings (r = 0.83, 0.78, respectively). Goniometric and photographic measurements of clavicular tilt angle obtained by raters in this study may be considered reliable, and data obtained using the goniometric and photographic measurements are representative of radiographic findings of clavicular tilt angle.