Investigation on the Effects Induced by Tka Features on Tibio-Femoral Mechanics Part I: Femoral Component Designs

Abstract

The lack of awareness of the exact number of instantaneous centers of knee flexion/extension rotation leads to the presence in the market of total knee arthroplasty (TKA) femoral components designed under different hypotheses. Although single radius (SR) designs are thought to replicate the physiological behavior in a more realistic way, surgeons do not always agree about the veracity of their theoretical advantages with respect to the multiple radii components (J-curve (JC) design). Apart from clinical studies, up to now, any literature study biomechanically and exhaustively compares these two TKA solutions, thus a finite element analysis (FEA) has been carried out. In particular, two models were defined to analyze the performance of a SR design and a JC design with the same tibial component during gait cycle and squat motor task. Tibio-femoral kinematics and kinetics have been investigated comparing the resulting contact area between components, internal-external (IE) rotation, position and magnitude of the center of total forces due to contact pressure and polyethylene von Misses stresses. Results demonstrate that, for low demanding tasks, there are no significant differences between the two designs, however, during the squat motor task, some changes in contact force and increases in polyethylene stress were identified for the SR solution.

Investigation on the Effects Induced by Tka Features on Tibio-Femoral Mechanics Part Ii: Tibial Insert Designs

“…5 Then, only the followed procedure for designing the semi-constrained version of the PS prosthesis is presented here. The semi-constrained tibial insert was obtained from the design of the PS conventional insert.…”

Biomechanical Analysis of Augments in Revision Total Knee Arthroplasty

“…In detail, such design is a fix bearing, with symmetric condyles having a J-curved shape. Such design features are the most common in the industry [32,33].…”

Asymmetric polyethylene inserts promote favorable kinematics and better clinical outcome compared to symmetric inserts in a mobile bearing total knee arthroplasty

“…The tibia is fixed in the region corresponding to the ankle [11,18,24,41]. Loads and kinematics were applied to the femur to dynamically replicate walking and squatting motor [19,22,[34][35][36]. In particular, for the simulated gait task, the boundary conditions were defined by the ISO-14243-1 [22,35] in terms of flexion extension, axial force, anteroposterior translation and internal-external rotation.…”