Restoration of active motion of the shoulder is a major treatment goal for patients with shoulder conditions. Variability in clinical measurement of the shoulder motion can make it difficult to evaluate a patients' progress. This study investigated the utility of a widely available infrared system for measuring shoulder motion.

This study used the Microsoft Kinect system, which employs infrared laser light and depth sensing cameras to determine positions of the arm and shoulder. Measurements were made for 10, normal, adult volunteers using the Kinect system, with those results compared with measurements made using standardized, anterioposterior and lateral photographs, taken concurrently. Measurements were made in five different positions of abduction, flexion, rotation and cross body adduction. The relationship between the two measurement methods was determined using linear regression. The results of the ROM measurements as determined by the Kinect system was compared with the ability to perform the Simple Shoulder Test (SST).

For the 10 control subjects, the Pearson correlation coefficients for the different positions were 0.997, 0.992, 0.982 and 0.995. The average time to document the five motions in both shoulders was 4.8 minutes. The Kinect measures of active motion correlated with the patients' self-assessments of their ability to perform the SST, with Pearson correlation coefficients of 0.79 for abduction, 0.67 for flexion, 0.56 for external rotation, 0.5 for internal rotation and 0.33 for cross-body adduction.

This study found that an infrared system without attached markers can provide a quick and accurate measurement of range of motion in the upper limb.