Measuring the range of motion of the shoulder and elbow is a common practice for medical professionals. However, the accuracy and precision of various methods of assessment is not clear. Digital photography has been recently studied as a means to improve reliability, yet this method has yet to be confirmed as an accurate means to calculate range of motion. By comparing various methods to the proven accuracy of computer navigation, this study seeks to identify a gold standard measuring tool for shoulder and elbow range of motion.
We examined 10 whole cadaveric specimens. Six practicing clinicians participated by comparing results of shoulder and elbow range of motion against computer generated results. The accuracy and reliability were calculated using visual assessment, goniometer, and digital photography as means for assessing range of motion.
The average error of visual assessment over all planes of motion was 7.4º (SD 5.6º). The average error for the goniometer assessment was 5.7º (SD 4.7º) while the digital photography yielded an average error of 5.5º (SD 5.0). There was a significant difference between visual and photographic assessments (p=.0001) and visual and goniometer measurements (p=.0001), but not between goniometer measurements and photographic assessments (p=.127). Results for outliers produced by each modality showed visual assessment produced 29% outliers (SD 21%). Goniometer assessment yielded outliers of 17% (SD 18%) as did photography with 17% outliers (SD 23%). There was a statistical difference between the incidence of outliers with visual assessment versus both photographic and goniometer measurements (p=.0019).
This study demonstrates that digital photography does increase the accuracy of measuring range of motion in the upper extremity but no more than assessment with a goniometer. There is a similar statistically significant reduction in outliers with either photography or use of goniometer when compared to visual assessment alone.
In order to provide accurate patient data and perform accurate research we must identify a gold standard measuring tool for range of motion of the upper extremity.