Should acute anterior dislocations of the shoulder be immobilized in external rotation? A cadaveric study

Authors: Bruce S. Miller, MD, David H. Sonnabend, MD, Cameron Hatrick, MD, Sean O’Leary, MD, Jerome Goldberg, MD, Wade Harper, MD, William R. Walsh, PhD

References: J Shoulder Elbow Surg 2004 Nov-Dec;13(6):589-92.

Abstract
The high recurrence rate associated with anterior shoulder dislocations may reflect inadequate healing of a Bankart lesion when the arm is immobilized in internal rotation. The effect of external rotation (ER) of the humerus on the glenoid-labrum contact of Bankart lesions was examined in 10 human cadaveric shoulders. The contact force between the glenoid labrum and the glenoid was measured in 60° of internal rotation, neutral rotation, and 45° of ER in 10 human cadaveric shoulders. No detectable contact force was found with the arm in internal rotation. The contact force increased as the arm passed through neutral rotation and reached a maximum at 45° of ER. The contact force returned to 0 g when the arm was returned to neutral rotation. The mean contact force at 45° of ER was 83.5 g. External rotation significantly increases the labrum-glenoid contact force and may influence the healing of a Bankart lesion.