Abstract
3D-FEM models of two different types of PS type knee prosthesis were constructed using their CAD data. Model 1 has a non-symmetric design of the tibial insert surface, while Model 2 possesses a symmetric type surface. Deep flexional motion with and without internal rotation was adapted to assess the effects of such flexional motion on the stress states of the tibial inserts made from UHMWPE. Model 1 showed higher stress level than Model 2 under flexion without internal rotation, on the other hand, the stress level of Model 1 became smaller than that of Model 2 under flexion with internal rotation. It is thus concluded that the non-symmetric surface design is very effective for deep flexional motion with internal rotation that is the typical knee movement in vivo.
