Modular acetabular designs enjoy widespread use in THA procedures and demonstrate versatility in accommodating musculoskeletal acetabular pathologies. Their mechanical performance has continually improved through enhanced locking mechanism assemblies and shell-liner conformity. Recently, a number of “improved” polymers have emerged whose commonly heralded benefit is a reduction in polyethylene wear due to increased cross-linking concurrent with minimized oxidation. These processes, however, change the chemical structure of the polymer as well as affect the static mechanical properties and fatigue characteristics. Additionally, decreases in resistance to crack propagation due to the increased crystallinity have been reported. This is of concern as short-term failures of modular, acetabular components employing conventional polyethylene have been reported with liner separation and gross fracture in the absence of normal wear. This study evaluated the locking mechanism strength for three, contemporary, modular acetabular designs, which employ both conventional and highly cross-linked polyethylene liners..