Verifying the Accuracy of Digital Goniometer Range of Motion Measurements for In-Person and Telemedicine Visits

Abstract

INTRODUCTION This paper offers empirical evidence of the accuracy of the clinical application of the RateFast Goniometer smartphone app. Using multiple comparative measures and interrater reliability measures, this paper investigates the effective ness of this digital goniometer app for physicians practicing in both the office and in telemedicine clinical settings. METHODS Three experiments were performed to test the reliability of the RateFast Goniometer app. The first involved measuring preset angles to test its accuracy. The second experiment involved measuring randomly drawn angles to determine if switching users has any effect on the results. The last experiment measured shoulder angles (flexion and extension planes) of 53 volunteers to determine the accuracy of the RateFast Goniometer app in both haptic mode (for use in an in -person clinical setting) and camera mode (for use in a telemedicine clinical setting). RESULT In the first experiment, the average difference between measurements was 0.6° and the average standard deviation was 0.3°. In the second experiment, the angles measured with the RateFast goniometer were less than those measured with a protractor, averaging to a difference of 0.9°. In the third experiment, the haptic mode measurements and the camera mode measurements had an average difference of 1.2° and the standard deviation of the difference between haptic and camera measurements was determined to be 4.7° across all volunteers. CONCLUSION In all three experiments, the error rate found using the RateFast Goniometer app which is within the error tolerance according to the AMA Guides to the Evaluation of Permanent Impairment, Fifth Edition (AMA Guides), which stipulates that measurements of shoulder angles must be within 10% of one another. The RateFast Goniometer app and similar digital goniometer applications can be used to accurately measure angles in both in -person and telemedicine settings according to the standards of accuracy set forth in the AMA Guides.