# Mechanical Properties and Characteristics of the
## 3 Results  
The results of the morphological measurements of the MCL, ALL, and LCL are shown in Table 2. The width and thickness were measured at the joint line and the length was measured as the distance from the proximal to the distal attachments of each ligament. When reviewing the results of the width of the ligaments, the widest ligament was the MCL and the narrowest one the LCL; also, the mean widths of the MCL, ALL, and LCL were 11.19 mm, 5.49 mm, and 3.96 mm, respectively (\(p<0.01\)). The mean thickness values of the LCL and MCL were 2.58 mm and 2.14 mm, respectively, and there was no statistical difference between the LCL and MCL (\(p=0.09\)); meanwhile, that of the ALL was 1.52 mm, indicating it was the thinnest ligament relative to the other two (\(p<0.01\)). Table 3 presents the results of the mechanical properties elucidated using the universal test machine. The ultimate loads, which initiate ligament damage, according to the individual ligaments were as follows: MCL, 498.57 N; LCL, 263.22 N; and ALL, 146.64 N (\(p<0.01\)). The stiffness of the \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **MCL** & **ALL** & **LCL** \\ \hline Width (mm) & \(11.19\pm 2.78\) & \(5.49\pm 1.90\) & \(3.96\pm 0.98\) \\ Thickness (mm) & \(2.14\pm 0.70\) & \(1.52\pm 0.64\) & \(2.58\pm 0.95\) \\ Length (mm) & \(68.99\pm 19.01\) & \(34.00\pm 9.90\) & \(48.15\pm 5.79\) \\ Cross-sectional area (mm\({}^{2}\)) & \(24.54\pm 11.94\) & \(8.50\pm 5.06\) & \(8.76\pm 3.77\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Size measurement results of the ligaments. Figure 2: An MCL test curve and ultimate load, stiffness, and elastic modulus calculation. The slope represents stiffness in the load–extension curve and represents the elastic modulus in the stress–strain curve. MCL (71.97 N/mm) was greater than that of the LCL (69.70 N/mm); however, there was no significant difference (\(p\) = 0.75). The stiffness of the ALL was smallest among the ligaments (42.62 N/mm) (\(p<0.01\)). The elastic modulus of the MCL (326.75 MPa) was similar to that of the ALL (345.27 MPa). Although the elastic modulus of the LCL was the largest in terms of its numerical value (493.86 MPa), there was no statistically significant difference relative to the values of the other ligaments (\(p\) = 0.06). The damaged areas of the different ligaments that appeared during the failure test are described in Table 4. The damaged area in the MCL and ALL most prominently involved the mid-substance of the ligament at rates of 48% (10/21 cases) and 67% (14/21 cases), respectively. However, 48% (10/21 cases) of the LCL was damaged at the proximal attachment of the ligament, which includes the femoral attachment part of the LCL. All ligaments had the least damage present at the distal attachment point (i.e., where the ligament attached to the tibia or fibula). There was a clear dominant side of the upper and lower extremities dependent on the individual under assessment. The right-left difference might be apparent because the dominant side more often handled major movements and power. Therefore, the MCL, ALL, and LCL properties of this study were compared between the left and right sides (Table 5). There was no difference between the sides among all properties of the ligaments assessed in this study. Concerning differences in the properties according to sex, the ultimate load of the male cadavers was greater than that of the female cadavers for all ligaments (\(p<0.05\)). Moreover, the stiffness and elastic modulus of the male cadavers were greater than those of the female cadavers as numerical values but there was no significant difference in this regard between the sexes. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Damaged Area** & **MCL** & **ALL** & **LCL** \\ \hline Proximal attachment & 7 & - & 10 \\ Mid-substance & 10 & 14 & 4 \\ Distal attachment & 4 & 7 & 7 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Failure mode of the ligaments.