abstract
- Tribological behavior is one of the most critical factors determining the longevity and reliability of hip prostheses, as it directly influences wear performance and the generation of potentially harmful debris. This study presents a comparative evaluation of the tribological behavior of eight material pairs commonly used in hip implants, tested under non-conformal sliding conditions that better resemble contact scenarios in artificial joints. A custom-modified tribometer, equipped with a load cell for continuous monitoring of the coefficient of friction (CoF), was used together with a bovine serum-based lubricant to simulate synovial fluid. Two loads were applied to replicate distinct contact pressure regimes, particularly those relevant to metal-on-polymer (MoP) configurations. Wear volume was quantified via optical profilometry, and dominant wear mechanisms were analyzed using scanning electron microscopy (SEM). UHMWPE-based systems showed the lowest CoF values (¿ 0.1) and minimal wear (< 4.7 × 10¿6 mm3/Nm), while metal-on-metal (MoM) and ceramic-on-metal (CoM) pairs exhibited higher friction (0.2-0.26) and wear rates (up to 124.0 × 10¿6 mm3/Nm), especially when AISI 316L stainless steel was used. Alumina-on-alumina combinations demonstrated the best wear resistance overall. The results highlight the combined influence of contact pressure and material pairing on tribological behavior and demonstrate the value of using practical, cost-effective test configurations for early-stage material screening in hip implant design. © ASM International 2025.