Reliability and concurrent validity of a Smartphone, bubble inclinometer and motion analysis system form measurement of hip joint range of motion.
Charlton PC, Mentiply BF, Pua YH, and Clark RA. J Sci Med Sport. 2014; [Epub ahead of print].
Take Home Message: A Smartphone app for measuring passive hip range of motion in healthy, young men may be reliable and valid when compared to the measurement values of a motion analysis system and a bubble inclinometer.
Although smartphone applications can measure hip range of motion there is no literature to support their use when compared with a bubble inclinometer. Since the majority of clinicians own a smartphone there is a potential for clinicians to objectively measure hip range of motion efficiently and in a variety of settings. Therefore, Charlton and colleagues assessed the intra-tester reliability and validity of a smartphone application for the evaluation of hip flexion, rotation, and abduction. The authors recruited 20 healthy participants (average age 24 years) who were pain free at the time of testing. A single physiotherapist evaluated each participant twice (3 days apart). During each session, the physiotherapist measured passive hip range of motion on the right limbs using 3 tools: “Hip ROM tester” Smartphone app, bubble inclinometer, and a 9 camera marker-based motion capture system. Each movement was measured 3 times and the median value of each set was used for analysis. The physiotherapist measured hip flexion, abduction, adduction, supine internal rotation and external rotation, and sitting internal and external rotation. The smartphone application was reliable (consistent) between the two sessions for four of the seven motions, with abduction, adduction, and sitting external rotation being somewhat less reliable. In comparison, when the physiotherapist had the bubble inclinometer he/she was less reliable with abduction and sitting external rotation. Overall, the smartphone application had “good to excellent” relationships with the motion capture system in all measurements except supine external rotation, which had a “moderate to good association.” The bubble inclinometer displayed a “good to excellent” association in all 7 measurement thus the researchers concluded that the use of a Smartphone application was a valid and reliable measure of passive hip range of motion in young, active males.
The above conclusions pose some interesting implication for all clinicians who measure hip joint range of motion. The use of a smartphone application could potentially have a positive impact on clinical practice. Since many clinicians report having a smartphone, this will increase the portability and availability of the tool when compared to a bubble inclinometer. Furthermore, the use of a smartphone may also be more cost efficient for clinicians when compared to a bubble inclinometer although this difference may be nominal. While there are many positives to using a smartphone, all clinicians should be aware of some limitations of the current study. Firstly, the authors did not report data on multiple phones so they were unable to definitively conclude that 1 method was better. Further, only one physiotherapist tested the application and a co-author was an inventor of the application. It will be interesting to see if other groups can replicate these results using multiple clinicians and multiple devices. Until more analyses can be completed to more directly compare the devices themselves, it would be wise for clinicians who are interested in using a smartphone application to proceed with caution and test if they consistently get the same results when they use the application.
Questions for Discussion: Do you use a Smartphone in your daily practice? Do you use your smartphone to measure joint range of motion? If not, would you consider using a smartphone to measure joint range of motion if it proves to be reliable and accurate?
Written by: Kyle Harris
Reviewed by: Jeffrey Driban