# Different ISO Standards' Wear Kinematic Profiles Change the TKA Inlay Load
## 2 Materials and Methods
### Computational Model  
Kinematic Validation and Basic Model for ISO 14243-1:2002 (Force-Controlled)  
The validation computer model was based on the ISO standard 14243-1:2002 (force-controlled standard), and for the equal inlay design which was used in the experimental setup, a deep dish (DD) design was used. The CAD file was imported into Ansys Workbench software (V16; Ansys, Inc., Canonsburg, PA, USA). The femoral component, inlay, and tibial baseplate were positioned in a neutral starting position to conform with the ISO standard [9]. The tibial base plate was embedded in a round rigid body according to the ISO standard with a lateralisation of 7% of the width, equivalent to that in the experimental \begin{table}
\begin{tabular}{c c c c c} \hline
**Inlay Design** & **ISO Norm 14243-1:2002 (FC)** & **ISO Norm 14243-1:2009 (FC)** & **ISO Norm 14243-3:2014 (DC)** \\ \hline - & - & **Without PCL** & **With PCL** & **-** \\ \hline \multirow{4}{*}{\
\begin{tabular}{c} Cricate-Retaining \\ (CR) \\ \end{tabular} } & anterior/posterior spring: 30 \(N\)/mm & \multirow{4}{*}{-} & anterior spring: 44 \(N\)/mm \\  & torsional spring: 600 \(N\)mm/\({}^{\circ}\) & & posterior spring: 9.3 \(N\)/mm \\  & anterior/posterior spring: 30 \(N\)/mm & & torsional spring: 360 \(N\)mm/\({}^{\circ}\) & No spring—defined via \\  & torsional spring: 600 \(N\)mm/\({}^{\circ}\) & & Note: First \(\pm\)2.5 mm (a/p \\  & & spring) and \(\pm\)6\({}^{\circ}\) (torsional \\  & & spring) without constraint & \\ \hline \multirow{4}{*}{
\begin{tabular}{c} Deep Dsh (DD) \\ \end{tabular} } & anterior/posterior spring: 30 \(N\)/mm & & anterior spring: 44 \(N\)/mm \\  & torsional spring: & - & posterior spring: 9.3 \(N\)/mm \\  & 600 \(N\)mm/\({}^{\circ}\) & & torsional spring: 360 \(N\)mm/\({}^{\circ}\) & No spring—defined via \\  & & torsional spring: & Note: First \(\pm\)2.5 mm (a/p \\  & 600 \(N\)mm/\({}^{\circ}\) & & spring) and \(\pm\)6\({}^{\circ}\) (torsional \\  & & spring) without constraint & \\ \hline \end{tabular}
\end{table} 
Table 1: Overview of the different model conditions for ISO norms 14243-1:2002 force-controlled (FC), 14243-1:2009 FC (without posterior cruciate ligament (PCL) and with PCL), and 14243-3:2014 displacement-controlled (DC). tests. Flexion/extension was free, and the axis of the J-curved femoral component was developed according to the experimental setup. The boundary conditions of the tibial baseplate were established on the bottom of the rigid body representing the embedded tibial component in resin (Figure 1). For translational movement, it was free to move in the medial/lateral, anterior/posterior, and proximal/distal (axial) directions. For rotational movement, it was free to rotate internally/externally and was free in varus/valgus rotation. Rotation around the \(x\)-axis, which represented the slope axis, was restricted during the whole simulation according to the ISO standard and the experimental setup. Forces for anterior/posterior translation, internal/external rotation (torque), and axial force were also established on the resin body. The anterior/posterior force was applied to the posterior part, while the axial force and the rotational torque were applied to the bottom part of the resin body. Due to the 7% lateral translation of the tibia and inlay  
Figure 1: Structure of the finite element (FE) model with the degrees of freedom (DOF) for femur and tibia according to the International Organization for Standardization (ISO). component during implantation, the line of action of the forces was secured according to the ISO standard. Restraint system-simulating ligaments and a capsule environment were added to the simulation with a linear spring according to the ISO standard with 30 \(N\)/mm in the anterior/posterior direction with a linear spring element. A restraint system for internal/external rotation of the tibia was also implemented via a linear spring element, i.e., a torsional spring element with 600 \(N\)mm/\({}^{\circ}\).