New method to assess scapular upward rotation in subjects with shoulder pathology

Test-retest repeated measures and correlational design.

To examine the reliability and validity of a "modified" digital inclinometer to assess scapular upward rotation during humeral elevation in the scapular plane

Evidence exists that scapular motion is related to shoulder pathology; however, evaluation and treatment planning for shoulder rehabilitation often fails to include an objective assessment of scapular motion.

Two-dimensional measurements by the inclinometer were taken with the arm in a static position. These data were compared to 3-dimensional measurements obtained using a magnetic tracking device with the arm fixed and during arm movement. Both methods were used to assess scapular upward rotation positions with the arm at rest and at 60 degrees , 90 degrees , and 120 degrees of humeral elevation in the scapular plane. Both scapulae were tested on a total of 39 subjects, 16 with shoulder pathology and 23 without. Reliability was assessed using repeated measurements from the inclinometer. Validity was assessed using 2 separate comparisons: inclinometer and magnetic tracking device under static arm conditions and inclinometer and magnetic tracking device during active arm elevation. Reliability and validity were assessed at all 4 arm positions.

Intraclass correlation coefficients (ICC [3,1]) varied from 0.89 to 0.96. Pearson Product Moment correlation coefficients, used to assess validity of the static inclinometer, varied from r = 0.74 to 0.92 compared with the static magnetic tracking measures, and from r = 0.59 to 0.73 compared with the active magnetic tracking measures taken during arm elevation.

The "modified" digital inclinometer demonstrated good to excellent intrarater reliability and good to excellent validity when measuring scapular upward rotation during static positions of humeral elevation in the scapular plane.