Dl. Bartel et al., STRESSES IN POLYETHYLENE COMPONENTS OF CONTEMPORARY TOTAL KNEE REPLACEMENTS, Clinical orthopaedics and related research, (317), 1995, pp. 76-82
Contemporary knee designs differ considerably in the conformity that e
xists between the articulating surfaces of the femoral and tibial comp
onents. The thickness of the polyethylene components also varies from
design to design. Conformity and thickness affect the stresses associa
ted with surface damage and the subsequent generation of harmful polye
thylene debris. In this study, the stresses and strains caused by cont
act were calculated for 8 contemporary knee prostheses. Finite element
analysis using large-strain theory was used to determine the stresses
and strains for the minimum available polyethylene thickness and for
the knee in flexion. The greatest differences among designs was for th
e von Mises strain, which reached its maximum beneath the surface. The
differences in stresses were less notable because of the nonlinear ma
terial behavior of the polyethylene. This study also confirmed the adv
antages of designs that have more conforming articulating surfaces and
thicker polyethylene components.