The glenosphere in Univers Revers is made of which material?

• A. Titanium Alloy
• B. Cobalt Chrome
• C. Stainless Steel
• D. Polyethylene

Answer: (B)

The glenosphere is the metal ball part of a reverse shoulder prosthesis and must withstand repeated articulation against a polyethylene liner. Cobalt-chromium alloy is the standard choice because it offers high hardness, excellent wear and fatigue resistance, and good biocompatibility, making it durable for the bearing surface in this metal-on-polyethylene setup. Titanium alloys are used for other components where weight and osseointegration matter, but they are not the preferred bearing surface due to lower hardness. Stainless steel is less common for the articulating ball because of corrosion and wear concerns, and polyethylene is the polymer used for the humeral liner, not the glenosphere.