# Finite Element Analysis of a Novel Approach for Knee and Ankle Protection during Landing
## 3 Results
### Knee Protection  
As can be seen from Table 2, no matter the height of the jump, the peak von Mises values of the menisci and articular cartilages decreased visibly after wearing the brace. With the brace, there were 23.8%, 21.5%, and 13.8% decreases in the peak von Mises stress of the menisci at the heights of 0.4 m, 0.8 m, and 1.2 m, respectively. As for the articular cartilages, the maximum von Mises stress decreased by 19.4%, 14.2%, and 9.1%, respectively. This serves to show that the peak von Mises values of the menisci were always higher than those of the articular cartilages at the three jumping heights with and without the brace.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Height (m)**} & **Horizontal Force** & **Horizontal Force** & **Percentage Decline** \\  & **with Brace (N)** & **without Brace (N)** & **Percentage Decline** \\ \hline
0.4 & 210.77 & 143.24 & 32\% \\
0.8 & 270.91 & 196.82 & 27.4\% \\
1.2 & 347.45 & 251.87 & 27.5\% \\ \hline \hline \end{tabular}
\end{table}
Table 1: The average horizontal forces on the talus with and without the brace at 0.4 m, 0.8 m, and 1.2 m.  
Figure 4: Von Mises stress distribution of the inferior articular surface of the tibia in braced (right) and unbraced (left) conditions at (a) 0.4 m, (b) 0.8 m, and (c) 1.2 m.  
Figure 5 shows the stress distribution on the menisci in braced and unbraced conditions at the three jumping heights. It can be seen that stress concentrations were found to occur in the medial meniscus without the brace. In contrast, stresses were more evenly distributed in the medial and lateral meniscus after wearing the brace.  
In order to further clarify the results, the contact areas of the menisci and articular cartilages were investigated, as shown in Figure 6. Although the total contact areas did not change obviously after wearing the brace, the medial contact area decreased and the lateral contact area increased, resulting in a more uniform distribution.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Height (m)** & **Part Instances** & \begin{tabular}{c} **Peak Von Mises Stress** \\ **with Brace (MPa)** \\ \end{tabular} & \
\begin{tabular}{c} **Peak Von Mises Stress** \\ **without Brace (MPa)** \\ \end{tabular} &
\begin{tabular}{c} **Percentage Decline** \\ **Percentage Decline** \\ \end{tabular} \\ \hline
0.4 & \begin{tabular}{c} Menisci \\ Articular cartilages \\ Menisci \\ Articular cartilages \\ Menisci \\ Articular cartilages \\ Menisci \\ Articular cartilages \\ \end{tabular} & \begin{tabular}{c} 26.36 \\ 6.018 \\ 29.94 \\ 17.41 \\ 35.06 \\ 21.07 \\ 21.07 \\ \end{tabular} & \
\begin{tabular}{c} 20.08 \\ 6.018 \\ 23.51 \\ 14.94 \\ 14.94 \\ 30.22 \\ 19.15 \\ \end{tabular} &
\begin{tabular}{c} 23.8\% \\ 19.4\% \\ 21.5\% \\ 14.2\% \\ 13.8\% \\ 9.1\% \\ \end{tabular} \\ \hline \hline \end{tabular}
\end{table}
Table 2: The peak von Mises stress of the menisci and articular cartilages with and without the brace at 0.4 m, 0.8 m, and 1.2 m.  
Figure 5: Von Mises stress distribution of the menisci in braced (right) and unbraced (left) conditions at (**a**) 0.4 m, (**b**) 0.8 m, and (**c**) 1.2 m.