2011 Volume 35 Issue 3 Pages 771-773
We evaluated the anterior shoulder translation at 90° abduction in the scapular plane at various angles of external and internal rotation to elucidate which rotation position shows anterior instability in patients with recurrent anterior shoulder dislocation. Thirty-two shoulders of 31 patients with recurrent anterior dislocation were enrolled in this study. All had Bankart lesion and underwent operative treatment (arthroscopic Bankart repair or open Bankart & Bristow procedure). Under general anesthesia at supine position, the examiner kept the shoulder at 90° abduction in scapular plane, drew the humeral head anterior, and assessed the translation of humeral head to the glenoid from maximum external rotation to maximum internal rotation of every 10° interval. Eight shoulders showed the translation of humeral head over the rim of the glenoid and never reduced spontaneously (grade 3), 20 shoulders showed over the rim but reduced spontaneously (grade 2), and 4 shoulders showed run on the rim (grade 1). Twenty-eight shoulders (grade 3 and 2) were defined as a dislocation group and we investigated the range of rotation, in which humeral head showed over grade 2 translation. Almost all showed translation over grade 2 in the middle range of rotation but not in maximum external and internal rotation. The mean range in which the shoulders showed translation over grade 2 was from 5° internal rotation to 56° external rotation and the center of the range was 25° external rotation. The shoulders of grade 3 translation tended to show a broader range of translation over grade 2. In the shoulders with recurrent anterior dislocation, translation over grade 2 was seen in the middle range of rotation so establishment of stability in the middle range of rotation could be important to prevent recurrence after surgical treatment.
