Clinical relevance commentary in response to “The validity and reliability of DrGoniometer, a smartphone application, for measuring forearm supination”

[...]the authors also provide indices of standard error of measurement (SEM) and minimal detectable change for the DrG in assessing forearm supination and compare these to the current literature.Are these study findings ready to be used in practice? 1 Second, although the values for the intraclass correlation coefficients (ICCs) to suggest intrarater (0.87; 95% confidence interval [CI]: 0.748-0.936) and interrater reliabilities (0.76; 95% CI: 0.559-0.878) of the DrG in patients with DRF was good, the lower bound for the 95% CI was at or below the threshold for good reliability (ICC < 0.75).1 For the clinical use of a measure, it is usually suggested that reliability of the measure is as good as the lower bound of the ICC and should be interpreted as such.2 So, there is a chance that the reliability of the DrG can be below this threshold (ICC < 0.75) if the experiment is repeated. [...]the authors recognize that they do not provide any standardized guidelines regarding the distance between the smartphone camera and the affected forearm while capturing the image to assess supination. The important limitations that authors have identified are as follows: (1) the short retest span between two measurements for assessing intrarater reliability such that there is a possibility of a rater remembering his/her reading from the first measurement; (2) smaller sample size (N = 30) with even smaller number of exclusive participants, and among them, some were considered more than once in the sample pool if they participated more than once in data acquisition during their recovery from DRF; (3) finally, but most importantly, the lack of standardization of distance between the smartphone and forearm to be measured while operating the DrG application for assessing supination.