This review traces how the Walch classification of glenoid morphology in primary glenohumeral osteoarthritis evolved from its 1999 original to the 2016 Bercik modification and later additions. It focuses on the definitions, measurement methods, and reliability of the type B glenoid, especially the biconcave B2.
Before planning a shoulder arthroplasty, you must classify the glenoid, because retroversion and posterior bone loss drive polyethylene loosening and osteolysis. The mental model to carry: posterior subluxation comes first, then eccentric posterior erosion, producing the biconcave B2, and finally the uniconcave high-retroversion B3. B2 sits in the middle of this arc.
Know which measurement method you are using. The scapular axis method (modified, 3D CT) reads much higher subluxation than the original mediatrice method, so a raw percentage is meaningless without context. A practical pitfall: a biconcave glenoid with more than 25° retroversion is a B2, not a C. C is reserved for dysplastic retroversion not caused by erosion.
When ordering imaging, remember MRI and plain films approximate version but are unreliable for separating B2 from C, so get a scapular-plane CT when the erosion pattern will change your reconstruction plan.
This review traces how the Walch classification of glenoid morphology in primary glenohumeral osteoarthritis evolved from its 1999 original to the 2016 Bercik modification and later additions. It focuses on the definitions, measurement methods, and reliability of the type B glenoid, especially the biconcave B2.
Before planning a shoulder arthroplasty, you must classify the glenoid, because retroversion and posterior bone loss drive polyethylene loosening and osteolysis. The mental model to carry: posterior subluxation comes first, then eccentric posterior erosion, producing the biconcave B2, and finally the uniconcave high-retroversion B3. B2 sits in the middle of this arc.
Know which measurement method you are using. The scapular axis method (modified, 3D CT) reads much higher subluxation than the original mediatrice method, so a raw percentage is meaningless without context. A practical pitfall: a biconcave glenoid with more than 25° retroversion is a B2, not a C. C is reserved for dysplastic retroversion not caused by erosion.
When ordering imaging, remember MRI and plain films approximate version but are unreliable for separating B2 from C, so get a scapular-plane CT when the erosion pattern will change your reconstruction plan.