Comparison of Different Methods of Measuring Finger Range of Motion via Telehealth.

PURPOSE: This study examined the accuracy and reliability of measuring total motion of the fingers via telehealth using the following three different methods: (1) goniometry, (2) visual estimation, and (3) electronic protractor. Measurements were compared with in-person measurement, which was assumed to be the reference standard.

METHODS: Thirty clinicians measured finger range of motion from prerecorded videos of a mannequin hand with articulating fingers, which was posed in extension and flexion that simulated a telehealth visit, using a goniometer with results blinded to the clinician (blinded goniometry), visual estimation, and an electronic protractor, in random order. Total motion was calculated for each finger and for all four fingers in sum. The experience level, familiarity with measuring finger range of motion, and opinions of measurement difficulty were assessed.

RESULTS: Measurement with the electronic protractor was the only method equivalent to the reference standard within 20°. Remote goniometer and visual estimation did not fall within the acceptable error margin of equivalence, and both underestimated total motion. Electronic protractor also had the highest interrater reliability (intraclass correlation [upper limit, lower limit], 0.95 [0.92, 0.95]); goniometry (intraclass correlation, 0.94 [0.91, 0.97]) was nearly identical, whereas visual estimation (intraclass correlation, 0.82 [0.74, 0.89]) was much lower. Clinicians' experience and familiarity with range of motion measurements had no relationship with the findings. Clinicians reported visual estimation as the most difficult (80%) and electronic protractor as the easiest method (73%).

CONCLUSIONS: This study showed that traditional in-person forms of measurement underestimate finger range of motion via telehealth; a new computer-based method (ie, electronic protractor) was found to be more accurate.

CLINICAL RELEVANCE: The use of an electronic protractor can be beneficial to clinicians measuring range of motion in patients virtually.