Reliability and concurrent validity of mobile health technology for patient self-monitoring in physical rehabilitation

BACKGROUND: Forearm pronation and supination are important for everyday functional tasks and some recreational activities. Healthcare providers use reliable and valid tools during the physical rehabilitation process to measure joint range of motion (ROM), assess functional mobility, guide decisions for skilled interventions, and progress a plan of care. Since the onset of the COVID-19 pandemic, both healthcare providers and patients benefited from mobile health technologies that have emerged, which can be used by patients in the home to monitor ROM and assist the healthcare provider in guiding the rehabilitation process when utilizing telehealth. PURPOSE: The goal of this study was to investigate the reliability and concurrent validity of a smartphone application for obtaining goniometric measurements of forearm pronation and supination. METHODS: This study consisted of 83 participants that were recruited on a voluntary basis from an academic institution. An iPhone with the application Clinometer and a standard goniometer (SG) were utilized to obtain goniometric measurements of forearm pronation and supination. The intraclass correlation coefficient (ICC) was used to analyze intrarater reliability, and the Pearson correlation coefficient was used to analyze concurrent validity. Scatterplots with regression lines were created to visually display the results. RESULTS: The smartphone demonstrated strong correlations for both pronation and supination (r = 0.71, P < .001; r = 0.73, P < .001). This study demonstrated overall good-excellent intrarater reliability and good concurrent validity for the smartphone application with a higher test-retest reliability in the measurement of forearm pronation compared to supination. CONCLUSIONS: This study concludes that the reliability and concurrent validity of the smartphone was consistent with the SG for assessing forearm pronation and supination. It may be of value to further investigate interrater reliability between patient and healthcare practitioner, and report on the ease of use to assess ROM with a smartphone.