This study proposes a modified Walch classification for glenoid morphology in primary glenohumeral osteoarthritis. It adds two new types (B3 and D), refines the A2 definition, and tests whether these changes improve classification reliability. Three fellowship-trained surgeons classified 129 glenoids using both systems on 3D CT reconstructions.
The original Walch system left two common morphologies without a home: the severely retroverted monoconcave glenoid (landed in C or A2 by mistake) and the anteverted or anteriorly subluxated glenoid (simply unclassified).
When you order preoperative CT for shoulder arthroplasty, use 3D reconstruction reformatted in the scapular plane — 2D CT underestimates retroversion and will mislead your classification.
If the glenoid is monoconcave with posterior wear and retroversion ≥15° or posterior subluxation ≥70%, classify it B3 and plan accordingly: eccentric reaming alone will perforate the glenoid wall, so augmented components, bone grafting, or reverse arthroplasty must be on the table.
Any anteverted or anteriorly subluxated glenoid is a D. Standard anatomic arthroplasty carries unacceptable anterior instability risk, and no reliable published treatment algorithm existed at the time this paper was written. The 16.3% revision rate for anatomic arthroplasty in biconcave (B2) glenoids underscores why accurate preoperative classification changes outcomes, not just nomenclature.
This study proposes a modified Walch classification for glenoid morphology in primary glenohumeral osteoarthritis. It adds two new types (B3 and D), refines the A2 definition, and tests whether these changes improve classification reliability. Three fellowship-trained surgeons classified 129 glenoids using both systems on 3D CT reconstructions.
The original Walch system left two common morphologies without a home: the severely retroverted monoconcave glenoid (landed in C or A2 by mistake) and the anteverted or anteriorly subluxated glenoid (simply unclassified).
When you order preoperative CT for shoulder arthroplasty, use 3D reconstruction reformatted in the scapular plane — 2D CT underestimates retroversion and will mislead your classification.
If the glenoid is monoconcave with posterior wear and retroversion ≥15° or posterior subluxation ≥70%, classify it B3 and plan accordingly: eccentric reaming alone will perforate the glenoid wall, so augmented components, bone grafting, or reverse arthroplasty must be on the table.
Any anteverted or anteriorly subluxated glenoid is a D. Standard anatomic arthroplasty carries unacceptable anterior instability risk, and no reliable published treatment algorithm existed at the time this paper was written. The 16.3% revision rate for anatomic arthroplasty in biconcave (B2) glenoids underscores why accurate preoperative classification changes outcomes, not just nomenclature.