Computational prediction of running-in wear in hard-on-hard dual mobility total hip prostheses during the gait cycle

Wear during the early running-in phase is a critical factor affecting the long-term performance of total hip prostheses, particularly in dual mobility systems that incorporate two articulating interfaces to enhance joint stability and reduce the risk of dislocation. This study presents a detailed computational investigation into the running-in wear behavior of hard-on-hard dual mobility total hip prostheses, focusing on three advanced bearing materials: cobalt chromium molybdenum (CoCrMo), aluminum oxide (Al 2 O 3 ), and polycrystalline diamond (PCD). Finite element analysis was employed, integrating Archard's wear model under gait cycle to simulate linear and volumetric wear across four key articulating regions: the acetabular cup, outer and inner surfaces of the acetabular liner, and the femoral head. Results demonstrated that PCD exhibited the lowest cumulative wear, with total linear and volumetric wear values reaching only 2.188 × 10 −4 mm and 1.170 × 10 −4 mm 3 respectively after 1 × 10 6 gait cycles, which is more than 95% lower than those of CoCrMo (1.170 × 10 −2 mm and 6.001 × 10 −3 mm 3 ). Al 2 O 3 displayed intermediate performance, reducing wear substantially compared to CoCrMo but not matching the exceptional resistance of PCD. The femoral head and the inner surface of the acetabular liner emerged as dominant contributors to early wear across all materials. These findings highlight the significant advantages of ultra-hard crystalline materials in minimizing tribological degradation and wear particle generation during the initial phase of implant function.