What is the effect of excessive retroversion on shoulder function?

Excessive retroversion, which refers to the backward angling of the glenoid component of the shoulder, can significantly impact shoulder function, particularly leading to anterior instability. This occurs because the excessive retroversion alters the mechanics and alignment of the shoulder joint, affecting how the humeral head articulates with the glenoid cavity.

In the context of excessive retroversion, the shoulder's normal kinematics are disrupted, which can result in insufficient glenoid coverage of the humeral head during movement. This misalignment increases the risk of the humeral head translating anteriorly, thus compromising joint stability. Additionally, it can lead to increased strain on the surrounding soft tissue structures, including the labrum and ligaments that stabilize the shoulder joint.

Overall, excessive retroversion does not enhance external rotation or limit internal rotation directly; rather, it primarily creates a scenario where the shoulder is more susceptible to dislocation or instability, particularly in anterior directions, making it crucial to consider retroversion when planning and executing total shoulder arthroplasty.