Retrospective multicenter cohort of 165 anatomic total shoulder replacements for primary osteoarthritis, all using the same uncemented metal-backed glenoid with a polyethylene insert. It asks two questions: does this implant survive long term, and can a worn PE insert simply be swapped while keeping the metal tray?
When you see an uncemented metal-backed glenoid with a polyethylene insert, expect the polyethylene to fail before the fixation does. Thin PE (4 mm), excessive total thickness (7 mm), and rigid metal backing raise insert stress and drive accelerated wear, which then feeds osteolysis and loosening.
The attractive selling point of these implants, that you can just exchange a worn insert or convert to reverse while keeping the tray, did not hold up: tray retention worked in only 3% of revisions because bone loss and soft tissue failure demand full glenoid removal.
Get a preoperative CT and classify the glenoid by Walch type. A biconcave type B with posterior subluxation is a red flag for recurrent subluxation, asymmetric wear, and early failure, and should push you toward an alternative such as reverse arthroplasty.
On surveillance films, treat new proximal humeral osteolysis in zones 7-8 as a marker of PE wear and consider revision before bone stock is lost.
Retrospective multicenter cohort of 165 anatomic total shoulder replacements for primary osteoarthritis, all using the same uncemented metal-backed glenoid with a polyethylene insert. It asks two questions: does this implant survive long term, and can a worn PE insert simply be swapped while keeping the metal tray?
When you see an uncemented metal-backed glenoid with a polyethylene insert, expect the polyethylene to fail before the fixation does. Thin PE (4 mm), excessive total thickness (7 mm), and rigid metal backing raise insert stress and drive accelerated wear, which then feeds osteolysis and loosening.
The attractive selling point of these implants, that you can just exchange a worn insert or convert to reverse while keeping the tray, did not hold up: tray retention worked in only 3% of revisions because bone loss and soft tissue failure demand full glenoid removal.
Get a preoperative CT and classify the glenoid by Walch type. A biconcave type B with posterior subluxation is a red flag for recurrent subluxation, asymmetric wear, and early failure, and should push you toward an alternative such as reverse arthroplasty.
On surveillance films, treat new proximal humeral osteolysis in zones 7-8 as a marker of PE wear and consider revision before bone stock is lost.