Effect of Scapular Misalignment during Setup on Stability of the Shoulder

Multidirectional instability can result due to multiple factors like the increased retroversion, a hypoplastic posteroinferior rim, and decreased scapular abduction during arm elevation [1]. Biomechanical studies are often used to understand the changes in the shoulder biomechanics [1-4]. During a biomechanical study setup misalignment of the scapula can occur leading to anterior or posterior tilt, which is rotation around the glenoid height (superior-inferior axis) as shown in Figure1. In past only one study has investigated the effect of scapular inclination [1-4]. However, to our knowledge there is no other study that has evaluated the influence of scapular misalignment/tilt. This study aimed to understand the relationship between glenoid tilt/misalignment and glenohumeral joint stability. We hypothesized that the shoulder stability would not change with variation in very small variations of glenoid tilt.