Revisit to scapular dyskinesis: three-dimensional wing computed tomography in prone position

J Shoulder Elbow Surg. 2014 Jun;23(6):821-8. doi: 10.1016/j.jse.2013.08.016. Epub 2013 Nov 23.


Background: Three-dimensional (3D) wing computed tomography (CT) showed a high inter-rater reliability in assessing scapular dyskinesis.

Methods: The 330 scapular movements of 165 patients were classified into 4 types by 7 blinded observers. Then, 3D wing CT was performed with patients prone, and 4 blinded observers measured 5 angles, consisting of upward rotation (UR) superior translation (ST), anterior tilting (AT), protraction (PRO), and internal rotation (IR). The inter-rater reliability (IRR) of 2 methods was calculated, and cutoff values were determined for the 5 angles on the 3D wing CT images.

Results: The IRR was 0.783 for the observational method of scapular dyskinesis and 0.981 for 3D wing CT in the prone position. UR and ST angles were significantly larger in type 3 more than in the other types (P < .001, P < .001), and the AT angle showed a similar pattern in type 1 (P < .001). The PRO angle was significantly larger in types 1, 2, and 3 more than in type 4 (P < .001, P < .001, P = .013), and the IR angle was significantly larger in type 2 more than in the other types (P < .001). The cutoff values of the 5 angles were UR, 117°; ST, 90°; AT, 8°; PRO, 99°; and IR, 51°. The UR angle showed a significant correlation with glenohumeral internal rotation deficit (odds ratio, 0.436; P = .029) and the IR angle with MDI (odds ratio, 8.947; P = .048).

Conclusion: The patients with a high UR angle showed a low rate of glenohumeral internal rotation deficit and those with a high IR angle had a high rate of the MDI in affected shoulder by the determinant of the cutoff value of the 5 angles.

Level of evidence: Level III, development of diagnostic criteria with nonconsecutive patients, diagnostic study.

Keywords: 3D wing CT; Scapular dyskinesis; concomitant disease; cutoff value; inter-rater reliability; observational method; prone position.

Publication types

  • Observational Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Animals
  • Biomechanical Phenomena
  • Child
  • Dyskinesias / diagnostic imaging
  • Dyskinesias / physiopathology
  • Female
  • Humans
  • Imaging, Three-Dimensional
  • Male
  • Middle Aged
  • Prone Position
  • Range of Motion, Articular
  • Reproducibility of Results
  • Scapula / diagnostic imaging*
  • Scapula / physiopathology
  • Shoulder Joint / diagnostic imaging*
  • Shoulder Joint / physiopathology
  • Tomography, X-Ray Computed
  • Young Adult