The Role of Porosity in Improving the Biomechanical Performance of Total Knee Arthroplasty: A Finite Element Perspective

Total Knee Arthroplasty (TKA) aims to relieve knee dysfunction caused by osteoarthritis or injury, but its success is hindered by implant failure. This study examines the impact of implant porosity on the biomechanical performance of TKA implants. We utilized Finite Element Analysis (FEA) to evaluate the biomechanical performance of porous TKA implants under realistic loading conditions. A 3D patient-specific model of a knee joint was created from CT scans of a 35-year-old male. The commercial TKA CR model (Sigma ${ }^{\circledR}$ FixedBearing Knees - DePuy Synthes) was designed using CATIA software. The bone models were assigned inhomogeneous material properties based on Hounsfield units from CT images. The FEA model included 66680 nodes and 399427 elements for bone tissues and 30996 nodes, 9890 linear hexahedral, and 129860 linear tetrahedral elements for implant components. The results revealed that implant porosity significantly affects stress distribution. Implants with $\mathbf{2 5 \%}$ porosity demonstrated optimal stress distribution, reducing von Mises stress in both femoral and tibial components. Higher porosity levels (e.g., 60%) risked implant failure due to reduced compressive yield strength. Porosity in TKA implants enhances biomechanical performance by improving stress distribution and reducing stress shielding. A $\mathbf{2 5 \%}$ porosity level is optimal, balancing biomechanical benefits and structural integrity, potentially leading to better patient outcomes and longer implant lifespans.