Computational Simulation of Femoral Stem Subsidence Patterns in Total Hip Arthroplasty Using Nigerian Population-Specific Femoral Geometry: A Finite Element Analysis Study

Total hip arthroplasty outcomes depend critically on the compatibility between prosthetic stem geometry and patient femoral canal morphology. Current implant designs are predominantly based on Western anthropometric datasets, and there is growing evidence that proximal femoral geometry varies across populations, potentially contributing to suboptimal fit and early stem subsidence in African patients. This study uses finite element analysis (FEA) and computational simulation to characterise femoral stem subsidence patterns in total hip arthroplasty using Nigerian population-specific femoral geometry derived from a radiographic and CT-scan dataset of 300 Nigerian adults across all geopolitical zones. Phase one involves a morphometric analysis of proximal femoral geometry including canal flare index, canal-calcar ratio, and cortical index, comparing Nigerian measurements to published European and Asian reference datasets. Phase two creates patient-specific three-dimensional finite element models of the proximal femur using segmented CT data, material properties assigned from quantitative CT Hounsfield values. Three standard cementless stem designs will be virtually implanted, and simulations run under physiological loading conditions to compute interface micromotion, stem subsidence, and stress shielding patterns. Phase three develops design optimisation recommendations for a Nigeria-adapted cementless stem. The study hypothesises that Nigerian femoral geometry exhibits systematically different canal flare indices from European norms, generating unique subsidence patterns that are not adequately addressed by standard commercial stems. This computational research generates original biomechanical data with direct clinical translation potential for arthroplasty practice. Keywords: finite element analysis, total hip arthroplasty, femoral morphology, stem subsidence, Nigerian population.