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Updated: May 16, 2026
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Video Movement Analysis Using Smartphones (ViMAS): A Pilot Study
Published on: March 14, 2017
Reliability of a smartphone-based goniometer for knee joint goniometry
Giorgio Ferriero1, Stefano Vercelli, Francesco Sartorio
1Unit of Occupational Rehabilitation and Ergonomics, Salvatore Maugeri Foundation, IRCCS, Scientific Institute of Veruno, Veruno, Italy. giorgio.ferriero@fsm.it
Summary
This study validates DrGoniometer (DrG), a smartphone app for knee joint angle measurement. DrG demonstrates high reliability, offering an easier alternative to traditional photographic goniometry.
Area of Science:
- Biomedical Engineering
- Rehabilitation Technology
- Clinical Measurement
Background:
- Joint goniometry is crucial in rehabilitation, often using complex photographic methods.
- Smartphone applications offer potential for simplified, accessible goniometry.
- DrGoniometer (DrG) is a novel smartphone application for photographic-based goniometry.
Purpose of the Study:
- To assess the reliability of the DrGoniometer (DrG) smartphone application for measuring knee joint angles.
- To compare DrG measurements against a universal goniometer (UG).
Main Methods:
- Validation study involving two controlled conditions: fixed participant measurements and analysis of a picture set.
- Four raters performed repeated measurements with DrG and UG.
- Ten additional raters measured knee angles (20-145°) from 35 clinical images using DrG.
Main Results:
- High inter-rater and intra-rater correlations ( > 0.958) for DrG measurements.
- Agreement with the universal goniometer showed limits of agreement of -7.5/+10.7° and -6.6/+7.5°.
- DrG proved to be a reliable method for knee joint angle assessment.
Conclusions:
- DrG is a reliable and user-friendly mHealth application for knee goniometry.
- It presents a viable alternative or supplement to existing photographic goniometric methods.
- Further research is recommended to evaluate DrG's reliability for other joint measurements.
