Abstract: Porous structure in orthopedic prosthesis may reduce micromotion and increase the service life of implants. The purposes of this study were to compare the infuence of the tibial stems with solid and porous structures in Total Knee Arthroplasty (TKA) on knee joint and prostheses, and to improve the mechanical stability of the host bone by seeking favorable structure for the tibial stem. The Finite Element (FE) models of TKA knee with four diferent structures in the middle segment of the tibial stem (i.e., solid, cubic, truncated cubic, and octahedral structures) were constructed. The distributions of von Mises stress in the knee joint, tibial prosthesis and proximal tibia, and the compressive stresses of the tibial prosthesis and ultra-high-molecular-weight polyethylene for the four FE models were analyzed. The results showed that the tibial stem flled with the octahedral structure has the best mechanical performance among the above four types of tibial stems. It could efectively reduce the stress concentration and stress shielding efects, and provide an improved mechanical environment for knee joint after TKA. This study would shed some lights on the design and fabrication of porous implants targeted to biomedical applications.

Key words: Total knee arthroplasty, Tibial stem, Porous structure, Finite element analysis, Mechanical performance