The intra- and inter-observer reliability of interface pressure measurements of the Milwaukee brace in adolescents with hyperkyphosis

BACKGROUND: There is a lack of evidence in reliability of the modified sphygmomanometer to measure the brace-interface pad pressure in adolescents with Scheuermann's kyphosis (SK). OBJECTIVES: To evaluate the intra- and inter-observer reliability of modified sphygmomanometer for measuring interface pad pressure in the Milwaukee brace. METHODS: Two observers measured the pressure of the shoulder and kyphosis pads in Milwaukee brace on 33 adolescents with SK with an average age of 14.67 +/- 1.72 years and Cobb angle 64.48 degrees +/- 7.53 degrees . All measurements were obtained in one day. The measurements were done in the inhalation and exhalation of tidal breathing during standing and sitting positions. The intraclass correlation coefficient (ICC), 95% confidence interval (CI), and linear mixed model ANOVA effects were calculated. RESULTS: The intra-observer reliability varied from a good ICC of 0.81 (0.66-0.90) to an excellent of 0.97 (0.95-0.98). The inter-observer reliability also varied from a good ICC of 0.82 (0.67-0.91) to an excellent of 0.96 (0.93-0.98). The linear mixed model ANOVA analysis showed that the rater, position, and breathing had a significant effect on the pad pressure measurements. CONCLUSIONS: The modified sphygmomanometer is a reliable tool to measure the pad pressure of the Milwaukee brace for adolescents with SK.