Reliability and validity of using smartphone sensor and photography to measure hand and upper extremity joint range of motion: A systematic review

BACKGROUND: Accurate Range of Motion measurement is vital for clinical decision-making. Traditional goniometers are reliable and valid tools but face challenges. Smartphones, with advanced technologies, are emerging as promising tools, necessitating validation for clinical integration. PURPOSE: The study aim is to appraise and synthesize the available evidence on the reliability and validity of smartphone sensors and photography in assessing the ROM of hand and upper extremity joints. STUDY DESIGN: Systematic review. METHODS: We searched the studies in which "smartphone sensor" or "smartphone photography" was employed as the method of upper limb ROM measurement from January 2001 to January 2023 to find relevant studies. We compared the studied methods to conventional goniometer as the gold standard and validated ROM measurement techniques. Two independent reviewers (SM and ES) assessed the methodological quality of reliability and validity of both category of studies using the Quality Appraisal Tool for studies of diagnostic Reliability (QAREL) and the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tools, respectively. Qualitative synthesis was the preferred method of summarizing and presenting the results. RESULTS: A total of 31 studies were included in this study. The sample size across studies ranged from 10 to 171, and the mean age was 41 years old. Eleven out of 12 studies included in the photography category stated the good to excellent reliability or validity with respect to the goniometric measurements. Eight studies in the smartphone sensor category reported excellent reliability or validity (47%), seven studies stated good level of reliability or validity (41%), and two studies reported average or moderate level of reliability (12%). The quality assessment using the QAREL assessment tool was high in 11 studies (35%), moderate in 8 studies (26%) or low in 12 studies (39%). CONCLUSIONS: This review provides clinicians and researchers with evidence to support using smartphone photography and sensor applications as valid and reliable methods for ROM measurements.