How to assess scapular dyskinesis precisely: 3-dimensional wing computer tomography-a new diagnostic modality

Abstract

Aberrations in scapular motion are believed to be associated with the presence of shoulder or elbow pathologies. There are many methods to evaluate scapular kinematics, but they have certain limitations. Nevertheless, it is believed that appropriate rehabilitation for each type of scapular dyskinesis is important. Eighty-nine athletes were videotaped and seven blinded observers categorized scapular dyskinesis into 4 types, which was followed by 3-dimensional (3D) wing computer tomography (CT). Four blinded examiners evaluated 5 angles [upward rotation (UR), internal rotation (IR), anterior tilting (AT), superior translation (ST), and protraction (PRO)] on the 3D wing CT. Inter-rater reliability (IRR) was calculated for both the methods. CT scan measurements were compared with the 4 observational types to establish the validity. The IRR with observational assessment of scapular dyskinesis into 4 types was good, 0.780. The 3D wing CT analysis had a very high IRR, 0.972. There was a statistically significant correlation between observational assessment and 3D wing CT analysis. The UR angle, ST angle in type 3 scapular dyskinesis, and AT angle in type 1 scapular dyskinesis were increased as compared with those in the other types of scapular dyskinesis. All these measurements were made in the resting position of the scapula. The 3D wing CT analysis allows precise quantification of a position associated with scapular dyskinesis. Therefore, 3D wing CT can be considered as an alternative method for assessing scapular dyskinesis.