Video examination via the smartphone: A reliable tool for shoulder function assessment using the constant score.

Background: The use of video examinations (VE) may improve patient care by offering them a low-cost and easy access to physicians, save traveling expenses and shorten waiting time. The aim of this study was to validate the use of Smartphones for distant assessment of shoulder function by comparing the Constant scores (CS) of patients obtained by both VE and conventional face-to-face (FTF) examination.

Methods: Fifty-one subjects (age 19-80 years; women:men 18:33) who presented to a shoulder clinic with a variety of complaints were prospectively recruited and underwent FTF and VE in alternating order. CS obtained by the two methods were compared. Four patients were unable to complete the VE due to technical problems or non-compliance.

Results: Forty-seven (92%) subjects successfully completed both examinations. The mean difference in CS was -0.53 points (95%CI: -2.6:1.6), with limits of agreement of -7.7:6 points. Agreement of correlation coefficient, accuracy and precision were 0.91 (95%CI: 0.86:0.96), 0.99 (95%CI: 0.92:1.00) and 0.91 (95%CI: 0.86:0.96), respectively.

Conclusion: VE can obtain a reliable estimate of shoulder function. The mean video CS was only -0.53 points from the mean frontal CS. Individual variations of CS did not exceed a 7-point distance from the "gold standard" estimate.