Quantitative Analysis of Scapular Winging Using Moire Topography.

Objectives: Moire Topography (MT) is a non-invasive technique that uses patterned light projection and has been used to qualitatively characterize scapular winging. The purpose of the present study was to quantitatively characterize scapular winging using a novel method of MT.

Methods: A total of 20 shoulders in ten healthy subjects were analyzed. The mean age for subjects was 27.9 ± 1.0 years and mean BMI was 22.8 ± 2.8. Two scenarios were used to simulate scapular winging: Group 1) the hand-behind-back (HBB) position and Group 2) weighted scaption after a muscle fatigue protocol. A calibration object was used to validate the MT method. This was followed by a use of a control object with known dimensions (OKD) to evaluate subjects. The measured height (z) of the OKD with MT, as determined by the known dimensions of the OKD, was then compared to the scapula winging in Groups 1 and 2. Scapular winging was characterized by measuring the height or prominence (z) of the scapula.

Results: There were significant differences between the baseline scapular measurements and scapular winging measurements in both Group 1, 4.0 cm ± 1.3 (P=0.0004), and Group 2, 3.7 ± 1.6 (P=0.0178). Scapular winging was most prominent with the hand in the highest position on the back in Group 1 and at lower degrees of scaption (<60 degrees) in Group 2.

Conclusion: Quantitative characterization of scapular winging was achieved using a novel method using MT. Scapular winging was found at lower degrees of shoulder elevation. Future applications of this technique should focus on characterizing scapular winging in multiple planes in real-time and in patients with known shoulder pathology.