Radiographic assessment of scapular rotational tilt in chronic shoulder impingement syndrome.

This study presents an objective evaluation of both scapular upward and axial rotational tilts in shoulder impingement syndrome, using a scapular spine line defined on antero-posterior (AP) radiographs of the shoulder as the referential line. Twenty-seven patients with unilateral shoulder motion pain, who were diagnosed as having chronic shoulder impingement syndrome, were enrolled in the study. Scapular upward and axial rotational tilts were compared between the affected and contralateral shoulders. AP radiographs were obtained at shoulder abduction angles of 0 degrees, 45 degrees, and 90 degrees, and the X-ray films were digitized by computer. The upward and axial rotational tilts of the scapula were then evaluated on the digital images. In shoulder impingement syndrome, both upward and axial external rotations of the scapula were impaired at the painful arc angle of abduction. This tended to be more apparent for the axial rotation of the scapula than for the upward rotation. These reductions in scapular rotations reduce available clearance for the rotator cuff and humeral greater tuberosity as the shoulder is abducted.