Primary osteoarthritis with a Walch B2 (biconcave) glenoid is hard to treat because the humeral head is statically subluxated posteriorly and the glenoid is eroded. Anatomic total shoulder arthroplasty in this setting has high rates of loosening and instability. This retrospective series asks whether reverse arthroplasty, despite an intact rotator cuff, can solve both problems in older patients.
When you see primary OA with a biconcave (Walch B2) glenoid, remember why it is a trap: the humeral head sits posteriorly subluxated and the posterior glenoid is eroded, so an anatomic glenoid component rocks loose and re-dislocates.
The numbers to know are the anatomic-TSA failure thresholds: about 44% loosening/instability risk when neoglenoid retroversion is 27° or more, and about 11% instability when subluxation is 80% or more. This paper's argument is mechanical. A semiconstrained reverse implant removes the need to perfectly recenter the head, so it fixes instability and erosion in one operation.
Apply this selectively. The cohort was old (mean 74) and mostly female, and reverse for an intact cuff is off-label, so this is not a young-patient solution. One technical pearl worth carrying: when grafting a posterior defect, anchor the baseplate central peg in native scapular bone, not just in the graft. The only loosening in the series broke this rule.
Primary osteoarthritis with a Walch B2 (biconcave) glenoid is hard to treat because the humeral head is statically subluxated posteriorly and the glenoid is eroded. Anatomic total shoulder arthroplasty in this setting has high rates of loosening and instability. This retrospective series asks whether reverse arthroplasty, despite an intact rotator cuff, can solve both problems in older patients.
When you see primary OA with a biconcave (Walch B2) glenoid, remember why it is a trap: the humeral head sits posteriorly subluxated and the posterior glenoid is eroded, so an anatomic glenoid component rocks loose and re-dislocates.
The numbers to know are the anatomic-TSA failure thresholds: about 44% loosening/instability risk when neoglenoid retroversion is 27° or more, and about 11% instability when subluxation is 80% or more. This paper's argument is mechanical. A semiconstrained reverse implant removes the need to perfectly recenter the head, so it fixes instability and erosion in one operation.
Apply this selectively. The cohort was old (mean 74) and mostly female, and reverse for an intact cuff is off-label, so this is not a young-patient solution. One technical pearl worth carrying: when grafting a posterior defect, anchor the baseplate central peg in native scapular bone, not just in the graft. The only loosening in the series broke this rule.