# Morphometric Analysis and Three-Dimensional Computed Tomography Reconstruction of Thai Distal Femur
## 4 Discussion  
The morphometric parameters of the distal femur are used for various applications, such as sex determination, racial and ethnic identification, and fundamental data for the design of knee prostheses [1; 4; 6; 18]. From a systematic review, the author found that the favorite method for the morphometric study is a measurement based on 3D models reconstructed by computer software in which most of the parameters were measured, including AP, ML, and ML/AP. Therefore, this study evaluated the morphometric of Thai distal femur based on 3D models reconstructed from computed tomographic (CT) data by reverse engineering techniques, which gave more accuracy and convenience than other methods [21; 22]. The reliability of measurement was examined by the intra-class correlation coefficient analysis. It was found that the intra- and inter-rater reliability coefficients were quite high (in a range of 0.84 to 0.98), indicating the excellent reproducibility of the measurement [36]. The result found that the intra-rater reliability for most parameters was higher than the inter-rater reliability. The main reason for the lower inter-rater correlation coefficients seems to be due to inconsistent identification of anatomical landmarks. However, the inter-rater reliability can be enhanced by clarifying the anatomical landmark descriptions, additional practice, and increased experience of the observers. The results of this study found that the important morphometric parameters, such as the average of mediolateral length (ML), medial anteroposterior width (MAP), and lateral anteroposterior width (LAP) of all subjects were as follows: 71.00 \(\pm\) 5.30 mm, 60.57 \(\pm\) 4.83 mm, and 63.10 \(\pm\) 4.48 mm, respectively. According to the comparison between genders, most of the male distal femur parameters were significantly higher than the female distal femur  
Figure 5: The relation between the total within-cluster sum of squares and number of clusters. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Size** & **AP (mm)** & **ML (mm)** & **AP (mm)** & **ML (mm)** & **AP (mm)** & **ML (mm)** \\ \hline
1 & 53 & 63 & 52 & 64 & 52 & 63 \\
2 & 58 & 68 & 56 & 62 & 54 & 67 \\
3 & 62 & 72 & 58 & 70 & 56 & 72 \\
4 & 62 & 76 & 60 & 67 & 58 & 72 \\
5 & 67 & 75 & 62 & 74 & 60 & 67 \\
6 & 67 & 79 & 64 & 72 & 63 & 72 \\
7 & - & - & 66 & 78 & 63 & 77 \\
8 & - & - & - & - & 67 & 78 \\ \hline \hline \end{tabular}
\end{table} 
Table 8: Sizing of the distal femoral component for the Thai population. parameters. These results were consistent with the previous studies [23, 24]. However, there was no significant gender difference in the ML/AP and ML/MAP ratio. This means that the ML/AP and ML/MAP ratio for Thais are approximately 1.26 and 1.18, respectively. It was confirmed that the mediolateral length was greater than the anteroposterior width. According to the comparison of Thai morphometric studies, the distal femur morphometric data of this study were quite different from those previously reported [23, 24]. In particular, the value of the femoral aspect ratio as shown in Table 4 was different. This may be a result of different definitions of measured parameters and measurement methods--for example, the measurement of distal femurs based on MRI images by simulation of distal femoral bone cut or intraoperative anthropometric measurement of resected Thai distal femora using a sterile Vernier caliper [23, 24], whereas this study used measurements based on a 3D model without resection of the distal femur. In addition, the results also showed that the Thai distal femur was different from those of other nationalities. Several studies reported that the morphology of the Caucasian distal femur was larger than that of the Asian distal femur, which is consistent with previous studies [20, 37, 38]. Most of the morphometric parameters in this study found that there was a significant difference compared to the Korean population [1, 2].