In Walch Classification B2, what is primarily affected in addition to the posteriorly subluxed humerus?

In Walch Classification B2, the primary characteristics include not only the posteriorly subluxed humerus but also a retroverted glenoid with posterior rim erosion. This classification indicates that there is significant alteration in the glenoid morphology, particularly with respect to its orientation and structural integrity.

The retroversion signifies that the glenoid is tilted backward, which often occurs due to chronic instability or wear patterns associated with rotator cuff deficiency or arthritis. The posterior rim erosion complements this by reflecting damage to the bony structure at the back of the glenoid, which may result from repeated stress or mechanical loading due to the altered humeral positioning.

This combination of retroversion and posterior erosion is crucial as it directly impacts surgical planning and different approaches to arthroplasty. Understanding this classification helps surgeons to anticipate challenges in restoring joint function and stability during total shoulder arthroplasty.