Loosening performance of cemented glenoid prosthesis design pairs

Objective. The purpose of this pilot study (n=3) was to compare the loosening performance of glenoid prosthesis design pairs where only one design variable differed. Design. Glenoids were subjected to dynamic edge loading in a biaxial test setup. Background. Glenoid component loosening is the primary concern in total shoulder arthroplasty. Methods. After the humeral head was cycled 100,000 times to the superior and inferior edges of the glenoid, the tensile edge displacements were measured under superior and inferior off-center loading. Results and conclusions. Based on this study, a rough-backed design had dramatically better loosening performance than a smooth-backed; curved-backed was superior to flat-backed; a less-constrained articular surface was better than a more-constrained articular surface; pegs outperformed a keel; threaded pegs were marginally preferable to cylindrical pegs; and an all-polyethylene design rocked slightly less than a metal-mesh-backed design.