Date of Award

January 2016

Document Type


Degree Name

Medical Doctor (MD)



First Advisor

Theodore A. Blaine


Measurement of range of motion (ROM) is an integral part of the shoulder exam, and an efficient and accurate tool to measure ROM would be valuable for orthopaedic surgeons, physical therapists, and other clinicians. The present study tests the accuracy and validity of a novel smartphone application (yROM Goniometer) to measure shoulder ROM in patients seen in clinic for shoulder pathology. The app calculates ROM from the orientation of the phone as it is held in the user’s hand during ROM movements.

The app was tested with patients presenting with shoulder pathology in clinic. Nineteen shoulders from 18 patients were tested. Subjects were given the phone with instructions for using the app to measure their shoulder ROM for abduction, scapular plane elevation (scaption), abducted internal and external rotation (IR90 and ER90), and external rotation at side (ER). Simultaneously, measurements were taken with a manual goniometer by the examiner. The two sets of measurements were compared using intraclass correlation [ICC (2,1)] and standard error or measurement (SEM).

All movements showed near-perfect correlation with goniometer measurements, with ICC (2,1) values of 0.968 (abduction), 0.969 (scaption), 0.875 (ER90), 0.925 (IR90), and 0.904 (ER). SEM values were 1.9° (abduction), 1.8° (scaption), 4.1° (ER90), 2.4° (IR90), and 2.7° (ER).

The measurements from yROM were accurate and valid when compared to a manual goniometer, with near-perfect ICC (2,1) correlation for all shoulder ROM movements. The SEM is similar to previously reported errors of measurement with manual goniometry and other smartphone goniometers. The novel app is an accurate, valid, and clinically useful tool for clinicians and patients to measure shoulder ROM.


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