Validation of an on-screen application-based measurement of shoulder range of motion over telehealth medium

Shoulder range-of-motion (ROM) assessment is vital for the follow-up evaluation of operated patients and for the outcome-based research studies. The aim of this study was to investigate the accuracy and reliability of a remote on-screen application (app)-based method of shoulder ROM measurement through a telehealth medium.

A consultant shoulder surgeon, a board-certified orthopedic resident, and a graduate medical doctor served as the examiners. The cohort consisted of 24 healthy volunteers and 16 symptomatic patients with expected shoulder ROM deficits. Shoulder ROM was first examined physically using a goniometer in the clinic and then over Zoom remote conferencing using the protractor extension app of the Chrome browser.

Instrument validity was examined by comparing the goniometer method with the protractor app-based method of the expert shoulder consultant using Bland-Altman analysis. It showed only minor mean differences between the healthy volunteers and the patients in elevation (2.0° and 5.0°, respectively), abduction (2.0° and 3.0°, respectively), external rotation with the elbow adducted (1.9° and 0.2°, respectively), external rotation with the elbow abducted at 90° (0.4° and 4°, respectively), and internal rotation with elbow abducted at 90° (2.3° and 1.2°, respectively), with limits of agreement that were below the well-established minimal clinically important difference values. The intraclass correlation coefficient (ICC) values varied between 0.83 and 0.96 for the volunteers and between 0.90 and 0.98 for the patients, indicating excellent correlation between the 2 methods. The interobserver reliability between 2 examiners for the protractor app-based method as evaluated by ICC scores was excellent; it ranged between 0.86 and 0.98 for the volunteers and between 0.88 and 0.99 for the patients. Comparison of the protractor app-based method with the gold-standard goniometer method for the resident and the graduate doctor showed excellent ICC values.

A protractor app-based method of measuring shoulder ROM over a telehealth medium is accurate and reliable compared with a clinical goniometer method. This validated method can be used during remote telehealth consultation with significant benefits of saving patients travel and time during the COVID-19 (coronavirus disease 2019) pandemic and even later.