BACKGROUND
In recent years, different smartphone apps have been validated for joint goniometry, but none for goniometric assessment of gait after stroke.
OBJECTIVE
The aims of our work were to assess:1) to assess intra-rater reliability of an image-based goniometric app – DrGoniometer- in the measurement of the extension, flexion angles and range of motion of the knee during the hemiparetic gait of a stroke patient; (2) its validity comparing to the reference method (electrogoniometer) for flexion-extension excursion measurements; and the intra-rater agreement in the choice of the video frames.
METHODS
An left-hemiparetic inpatient following haemorrhagic stroke was filmed using the app while walking on a linear path. An electrogoniometer was fixed on the medial face of the affected knee in order to record the dynamic goniometry during gait. Twenty-one raters, blinded to measurements, were recruited to rate knee angle measurements from video acquired with DrGoniometer. Each rater repeated the same procedure twice, the second one at least one day after the first measure.
RESULTS
Results showed that flexion angle measurements are reliable (ICC95%=0.66, 0.34;0.85; SEM=4°), and adequately precise (CV=14%). Extension angles measurements demonstrated moderate reliability and higher degree of variation (ICC=0.51, 0.09;0.77; SEM 4°; CV=53%). ROM values were: ICC=0.23 (-0.21;0.60); CV=20%. Accuracy of DrGoniometer compared to the electrogoniometer was 7.3±4.7°. The selection of maximum extension frame revealed an accordance of 58% and 72% within a range of ±5 or ±10 frames, respectively; while the best flexion frame reported 86% of agreement for both range of 5 and 10 frames.
CONCLUSIONS
The results demonstrated moderate to good reliability concerning the maximum extension and flexion angles, while assessing ROM DrGoniometer showed poor intra-rater reliability. Flexion angle measurements seemed to be reliable according to ICC and SEM values and more precise with a limited dispersion of results DrGoniometer revealed a good accuracy in the measurement of range of motion. The agreement of the maximal extension frame was anyway adequate within 5 frames (59%) and noticeably increased within 10 frames (72%).
In conclusion, DrGoniometer was found to be a valid and reliable method for assessing knee angles during hemiparetic gait. Further studies are necessary to investigate inter-rater reliability and confirm our results.
