Background The knowledge of 3-dimensional (3D) scapular kinematics is essential for understanding the pathological lesions of shoulder and elbow in throwing athletes. To date, a number of studies about alterations of static scapular position, dynamic scapular motion, or scapular dyskinesis have been conducted, yet none of them have identified consistent pattern of altered scapular kinematics in throwing athletes.
Ojective To analyze the 3D scapular kinematics of dominant and non-dominant arms in baseball players with a pathological condition of shoulder or elbow.
Design Cross-Sectional Study.
Setting Baseball players from middle school to professional players.
Patients (or Participants) 319 baseball players who visited our clinic with the pathological condition of shoulder or elbow from December 2011 to August 2015.
Interventions (or Assessment of Risk Factors) The CT scan was performed using a 64-channel multidetector CT system in a prone position with the arms at the side of the body and at 150° forward elevation with the palms toward the body.
Main Outcome Measurements From 3D computed tomography, angular values of the scapula were compared between dominant and non-dominant arms with statistical analysis.
Results The scapular position of dominant arms showed significantly more AT, less ST at rest and more UR, IR and less ST, PRO, AT at 150° full FE compared to the non-dominant arms. The angular increment of scapular UR, IR, PRO, and AT during arm elevation increased significantly between the paired arms.
Conclusions When compared to the non-dominant arms, UR, AT and PRO with the arm at 150° FE of dominant symptomatic arms in baseball players tilted towards positive compensation while IR altered towards negative decompensation. In addition, the motion of the scapula increases significantly in dominant symptomatic arms, compared to the non-dominant arms.