Reliability and validity of goniometric iPhone applications for the assessment of active shoulder external rotation

ABSTRACT Purpose/hypothesis: The purpose of this study was to determine the reliability and validity of two smartphone applications: (1) GetMyROM – inclinometery-based and (2) DrGoniometry – photo-based in the measurement of active shoulder external rotation (ER) as compared to standard goniometry (SG). Participants: Ninety-four Texas Woman's University Doctor of Physical Therapy students from the School of Physical Therapy – Houston campus, were recruited to participate in this study. Materials/methods: Two iPhone applications were compared to SG using both novice and experienced raters. Active shoulder ER range of motion was measured over two time periods in random order by blinded novice and experienced raters. Results: Intra-rater reliability using novice raters for the two applications ranged from an intraclass correlation coefficient (ICC) of 0.79 to 0.81 with SG at 0.82. Inter-rater reliability (novice/expert) for the two applications ranged from an ICC of 0.92 to 0.94 with SG at 0.91. Concurrent validity (when compared to SG) ranged from 0.93 to 0.94. There were no significant differences between the novice and experienced raters. Conclusion: Both applications were found to be reliable and comparable to SG. A photo-based application potentially offers a superior method of measurement as visualizing the landmarks may be simplified in this format and it provides a record of measurement. Clinical relevance: Further study using patient populations may find the two studied applications are useful as an adjunct for clinical practice.