Finite Element Analysis of Collared Hip Prosthesis Cross-Sections Under Dynamic Loading and Wear Conditions for Durable Orthopedic Implant Design

Background/Objective: Traditional hip implant evaluations often overlook patient-specific dynamic loadings. This study investigates the performance of novel collared hip implant designs under walking conditions, focusing on geometric profiles and two common stem materials: Ti-6Al-4V and CoCr alloy. Methods: Patient-specific dynamic forces were applied using commercial finite element analysis, adhering to ISO and ASTM standards. Four cross-sectional profiles—circular, elliptical, oval, and trapezoidal—were initially evaluated for induced stresses and displacements. Subsequently, wear characteristics at implant junctions were analyzed, comparing CoCr (MC 1) and Ti-6Al-4V (MC 2) stems. The study also assessed the impact of using Ultra-High Molecular Weight Polyethylene (UHMWPE) acetabular cups. Results: The elliptical (CS 2) cross-sectional profile demonstrated superior performance. Junction analysis revealed that the CoCr stem (MC 1) exhibited a stem-to-head sliding distance four times higher and contact pressure 5.5 times higher than the Ti-6Al-4V stem (MC 2). Specifically, MC 1 showed 82% higher contact pressure and 89% greater sliding distance at the stem–head junction compared to MC 2. Additionally, utilizing UHMWPE cups effectively eliminated squeaking sounds attributed to CoCr cups due to superior wear resistance. Conclusions: The combination of an elliptical (CS 2) cross-sectional profile with a Ti-6Al-4V stem and UHMWPE acetabular cup offers optimal performance. This configuration significantly reduces wear and contact pressure, suggesting enhanced functionality and durability for hip implants under dynamic loading conditions.