Measurement of active shoulder motion using the Kinect, a commercially available infrared position detection system.
BACKGROUND
The shoulder's ability to participate in sports and activities of daily living depends on its active range of motion. Clinical goniometry is of limited utility in rigorously assessing limitation of motion and the effectiveness of treatment. We sought to determine (1) whether a validated position-sensing tool, the Kinect, can enable the objective clinical measurement of shoulder motion and (2) the degree to which active range of motion correlates with patient self-assessed shoulder function.


METHODS
In 10 control subjects, we compared Kinect motion measurements to measurements made on standardized anteroposterior and lateral photographs taken concurrently. In 51 patients, we correlated active motion with the ability to perform the functions of the Simple Shoulder Test (SST).


RESULTS
In controls, Kinect measurements strongly agreed with photographic measurements. In patients, the total SST score was strongly correlated with the range of active abduction. The ability to perform each of the individual SST functions was strongly correlated with active motion. The active motion in well-functioning patient shoulders averaged 155° ± 22° abduction, 159° ± 14° flexion, 76° ± 18° external rotation in abduction, -59° ± 25° internal rotation in abduction, and -3.3 ± 3.7 inches of cross-body adduction, values similar to the control shoulders. Use of the Kinect system was practical in clinical examination rooms, requiring <5 minutes to document the 5 motions in both shoulders.


CONCLUSIONS
The Kinect provides a clinically practical method for objectively measuring active shoulder motion. Active motion was an important determinant of patient-assessed shoulder function.
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA. Electronic address: matsen@uw.edu.
Frederick A
FA
Matsen
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Alexander
A
Lauder
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Kyle
K
Rector
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Peyton
P
Keeling
Department of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA, USA.
Arien L
AL
Cherones
D000203:Activities of Daily Living; D000328:Adult; D053587:Arthrometry, Articular / Q000295:instrumentation / Q000379:methods*; D035061:Control Groups; D005260:Female; D006801:Humans; D008297:Male; D009068:Movement / Q000502:physiology*; D012399:Rotation; D012782:Shoulder; D012785:Shoulder Joint / Q000502:physiology*; D055815:Young Adult
Shoulder; active; measurement; motion