# Mechanical Properties and Characteristics of the
## 4 Discussion
The elastic modulus of the MCL was similar to that of the ALL, while that of the LCL was larger; however, there was no significant difference between the three ligaments. There was no difference between the right and left sides among the different properties, but the properties of male cadavers were greater than those of female cadavers. Each ligament displayed a similar stiffness regardless of its size. However, when the stiffness is converted to the elastic modulus, which considers the cross-sectional area, it was harder to assess an average value because there was great deviation apparent due to the size of each ligament. Therefore, the stiffness should be preferentially considered when performing biomechanical simulations using these ligaments. There were some limitations in this study. Due to the ligaments that were harvested from the cadavers, their condition could differ from living human tissue, and the age of all the cadavers was old. Furthermore, in spite of the fact that the cross-sectional area of each ligament was not constant, the cross-sectional area was measured at the joint line as a rectangular shape for the ALL and MCL, and as an oval shape for the LCL. Finally, we performed the quasi-static test, and did not apply the various strain rates for the material test. Our strain rate was 10 mm/min. However, most of the comparable studies used different strain rates. Thus, it was difficult to completely compare our results with previous studies. Conceptualization, H.-J.C. and D.-S.K. ; methodology, D.-S.K. ; validation, H.-J.C.; formal analysis, H.-J.C.; investigation, D.-S.K. ; writing--original draft preparation, H.-J.C. and D.-S.K. ; writing--review and editing, D.-S.K. All authors have read and agreed to the published version of the manuscript. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (NRF-2016R1D1A1B03931207). \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Ligament** & **Author (Year)** & **N** & **Mean Age** & **Ultimate Load (N)** & \
\begin{tabular}{c} **Stiffness** \\ **(N/mm)** \\ \end{tabular} &
\begin{tabular}{c} **Elastic** \\ **Modulus (MPa)** \\ \end{tabular} \\ \hline \multirow{6}{*}{LCL} & This study (2020) & 21 & 77.1 & 263.2 \(\pm\) 93.1 & 69.7 \(\pm\) 22.9 & 493.9 \(\pm\) 99.0 \\ \cline{2-7}  & [PERSON] et al. (2001) & 10 & About 70 & 309.0 \(\pm\) 91.0 & 58.1 \(\pm\) 22.8 & - \\ \cline{2-7}  & [PERSON] et al. (2005) & 8 & 57.5 & 295.0 \(\pm\) 96.0 & 33.5 \(\pm\)13.4 & 183.5 \(\pm\) 110.7 \\ \cline{2-7}  & [PERSON] et al. (2006) & 13 & 70 & 460.0 \(\pm\) 163.0 & 82.0 \(\pm\) 25.0 & - \\ \cline{2-7}  & [PERSON] et al. (2012) & 9 & 81 & 392.0 \(\pm\) 104.0 & 59.0 \(\pm\) 12.0 & - \\ \hline \multirow{6}{*}{MCL} & This study (2020) & 21 & 77.1 & 498.6 \(\pm\) 119.6 & 72.0 \(\pm\) 23.5 & 326.8 \(\pm\) 225.2 \\ \cline{2-7}  & [PERSON] et al. (1983) & 5 & 55–90 & 465.0 \(\pm\) 190.0 & 60.0 \(\pm\) 22.0 & - \\ \cline{1-1} \cline{2-7}  & [PERSON] et al. (2012) & 9 & 81 & 799.0 \(\pm\) 209.0 & 63.0 \(\pm\) 14.0 & - \\ \hline \hline \end{tabular}
\end{table} 
Table 7: Comparisons of the mechanical properties of the LCL and MCL. **Conflicts of Interest**: The authors declare no conflict of interest. **Ethics Statement**: This research did not contain human and human-related material. Only donated cadavers (The Catholic University of Korea) were used, and all methods were carried out in accordance with relevant guidelines and regulations from the Catholic Institute for Applied Anatomy (Project identification number: R16-A014).