This 2018 narrative review by Domos, Checchia, and Walch formalizes the term 'Walch B0 glenoid' for posterior humeral head subluxation occurring before any cartilage or bone erosion. It reviews the pathophysiology, measurement controversies, and limited surgical evidence for this pre-osteoarthritic condition. The authors argue the condition begins as dynamic decentering and only later becomes fixed static subluxation.
Posterior humeral subluxation in young adults with shoulder OA was historically attributed to posterior glenoid erosion following the pattern Neer described. Walch's work reversed the sequence: subluxation comes first, then erosion — and B0 is the window before irreversible damage occurs.
When you see a young patient with shoulder pain, locking, and a feeling of instability but a negative apprehension test, think B0. These patients are frequently misdiagnosed as anterior instability. Axial CT with the arm in neutral rotation is the key imaging study. Confirm subluxation index >55%.
Do not assume that correcting glenoid retroversion will recenter the head. The best available data show version improves but subluxation persists or worsens after osteotomy. Functional improvement can occur without recentering, but the underlying decentering continues to load the posterior glenoid.
The scapulohumeral index (referenced to the Friedman/scapular line rather than the glenoid surface) may better capture the true alignment problem. Particularly when the glenoid is eroded or dysplastic and the glenohumeral index becomes unreliable.
This 2018 narrative review by Domos, Checchia, and Walch formalizes the term 'Walch B0 glenoid' for posterior humeral head subluxation occurring before any cartilage or bone erosion. It reviews the pathophysiology, measurement controversies, and limited surgical evidence for this pre-osteoarthritic condition. The authors argue the condition begins as dynamic decentering and only later becomes fixed static subluxation.
Posterior humeral subluxation in young adults with shoulder OA was historically attributed to posterior glenoid erosion following the pattern Neer described. Walch's work reversed the sequence: subluxation comes first, then erosion — and B0 is the window before irreversible damage occurs.
When you see a young patient with shoulder pain, locking, and a feeling of instability but a negative apprehension test, think B0. These patients are frequently misdiagnosed as anterior instability. Axial CT with the arm in neutral rotation is the key imaging study. Confirm subluxation index >55%.
Do not assume that correcting glenoid retroversion will recenter the head. The best available data show version improves but subluxation persists or worsens after osteotomy. Functional improvement can occur without recentering, but the underlying decentering continues to load the posterior glenoid.
The scapulohumeral index (referenced to the Friedman/scapular line rather than the glenoid surface) may better capture the true alignment problem. Particularly when the glenoid is eroded or dysplastic and the glenohumeral index becomes unreliable.