According to the Walch classification, which grade corresponds to posterior erosion of the glenoid causing a definitive paleo-glenoid and new-glenoid?

In the Walch classification of glenoid deformities, grade B2 specifically refers to posterior erosion of the glenoid that leads to significant changes in the glenoid surface, resulting in the formation of what is termed a "definitive paleo-glenoid" and a "new-glenoid." This classification is critical for understanding the underlying anatomy and planning appropriate surgical interventions in cases of glenohumeral arthritis and glenoid deformities associated with shoulder conditions.

The B2 grade indicates that the posterior erosion has advanced to the point where there is a distinct loss of glenoid bone, significantly impacting the joint's stability and biomechanics. Identifying this classification not only helps in determining the severity of the glenoid degeneration but also guides the selection of surgical strategies, including the potential for glenoid components that can accommodate or reconstruct the abnormal anatomy during total shoulder arthroplasty.