Measurement of Active Shoulder Motion Using the Kinect, A Commercially Available Infrared Position Detection System
Matsen FA, Lauder A, Rector K, Keeling P, Cherones AL. J Shoulder Elb Surg. 2015.
[Epub ahead of print]. http://dx.doi.org/10.1016/j.jse.2015.07.011.
Take Home Message: The Kinect provides a method to objectively measuring active shoulder range of motion.
Restoring active shoulder range of motion is a major goal in rehabilitation for patients with shoulder conditions. The Kinect has been validated with other motion capture systems, but its practical use in the clinical setting has not been examined. The Kinect is an inexpensive (<$150) commercially available system that projects an infrared laser light onto a body and reproduces a 3-dimensional body map using a computer database. This study first aimed to examine the relationships between active shoulder range-of-motion measurements based on an infrared position detection system (Kinect) or photographs among healthy control subjects. The authors also examined the efficiency of the Kinect in clinical practice and the relationship between patient self-reported function and Kinect measurements. The authors assessed 10 healthy participants (5 males and 5 females) with Kinect motion measurements and measurements made using standardized anteroposterior and lateral photographs. Control participants had no history of any shoulder diseases (e.g. arthritis, tendonitis, instability). Each control participant stood before the Kinect and actively positioned their arm in abduction, flexion, external rotation in abduction, internal rotation in abduction, and cross-body adduction. The person who measured the range of motion on the photographs was unaware of the Kinect-based measures. The authors also identified 51 shoulder clinic patients who had Kinect-based measurements of active shoulder range of motion and self-reported function by completing the Simple Shoulder Test (SST). Among the healthy control participants, the authors checked if the Kinect measurements related to the photographic measurements. Among the patients, the authors checked if Kinect measurements related with the patient’s shoulder function. Kinect measurements and photographic measurements were highly related with each other (all relationships were > 0.90 with 1.00 being exactly related) in healthy participants. Furthermore, the average differences between Kinect and photographic measures were less than 3.5 degrees. Among injured patients, relationships between Kinect-based active range of motion and SST scores were moderate. In the clinic setting, Kinect measurements required an average time of 4.8 minutes to record bilaterally range of motion.
These findings suggest that the Kinect provides a practical and inexpensive way of measuring shoulder active range of motion compared to expensive marker-based optical motion capture systems. Clinicians can expect a moderate and reasonable relationship between Kinect measurements and self-reported shoulder motion. The use of the infrared sensor technology to capture this data is inexpensive, mobile, and may provide efficiency between clinicians. With further research and modification, the Kinect could very well become the preferred alternative to the way shoulder active range of motion is documented. The Kinect could turn out to be a great tool for clinical evaluations.
Questions for Discussion: What is your preferred method of measuring shoulder active range of motion and why? How do you feel the Kinect measurements add up compared to goniometer use for effectively measuring range of motion?
Written by: Byron Campbell, Brittany Davis, and Liz Zwicker
Reviewed by: Jeffrey Driban
Matsen, F., Lauder, A., Rector, K., Keeling, P., & Cherones, A. (2015). Measurement of active shoulder motion using the Kinect, a commercially available infrared position detection system Journal of Shoulder and Elbow Surgery DOI: 10.1016/j.jse.2015.07.011