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.
[Epub ahead of print].

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

Related Posts:

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