This study uses 3-D CT quantitative analysis to identify two new glenoid subtypes — B3 and C2 — that fall outside the original Walch classification for glenohumeral osteoarthritis. The authors analyzed 155 preoperative shoulder CT scans to define premorbid and pathologic anatomy, proposing a modified 7-subtype classification system.
The original Walch classification lumped high-retroversion glenoids into a single "C" category regardless of whether the retroversion was congenital or acquired — a distinction that has completely different surgical implications.
When you see a shoulder with high pathologic retroversion and a centered or nearly-centered humeral head, get a 3-D CT and assess premorbid version before calling it a C glenoid. If premorbid version is near-normal (~7°) with significant medialization, this is a B3. An acquired deformity that likely represents end-stage B2 progression, not dysplasia.
For C2 glenoids, the dysplastic baseline means correction targets are different from a standard B2 biconcave glenoid. Treating a C2 like a B2 risks under-correcting the native version deformity. Osseous anatomy alone explains less than 30% of humeral head subluxation in B2/B3 glenoids, so do not expect full centering from bone correction alone. Soft-tissue balancing matters too.
This study uses 3-D CT quantitative analysis to identify two new glenoid subtypes — B3 and C2 — that fall outside the original Walch classification for glenohumeral osteoarthritis. The authors analyzed 155 preoperative shoulder CT scans to define premorbid and pathologic anatomy, proposing a modified 7-subtype classification system.
The original Walch classification lumped high-retroversion glenoids into a single "C" category regardless of whether the retroversion was congenital or acquired — a distinction that has completely different surgical implications.
When you see a shoulder with high pathologic retroversion and a centered or nearly-centered humeral head, get a 3-D CT and assess premorbid version before calling it a C glenoid. If premorbid version is near-normal (~7°) with significant medialization, this is a B3. An acquired deformity that likely represents end-stage B2 progression, not dysplasia.
For C2 glenoids, the dysplastic baseline means correction targets are different from a standard B2 biconcave glenoid. Treating a C2 like a B2 risks under-correcting the native version deformity. Osseous anatomy alone explains less than 30% of humeral head subluxation in B2/B3 glenoids, so do not expect full centering from bone correction alone. Soft-tissue balancing matters too.