# Morphometric Analysis and Three-Dimensional Computed Tomography Reconstruction of Thai Distal Femur
## 3 Results
### Application of Morphometric Data to Analyze the Knee Prostheses for Thais  
In addition, this study provides essential data for improving the design of knee prostheses for the Thai population--for instance, to improve the design of the femoral component for total knee arthroplasty based on the morphometry of the Thai knee. Significant factors leading to the effectiveness of complete knee arthroplasty were sufficient for the \begin{table}
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**Parameters** & **Linear Regression Equation** & **Correlation** \\  & & **Coefficient (r)** \\ \hline AP vs. MAP & AP = \(-\)3.53 + 0.99 MAP & 0.958 \\ ML vs. TEA & ML = 15.77 + 0.64 TEA & 0.798 \\ MAP vs. LAP & MAP = 16.47 + 0.72 LAP & 0.766 \\ AP vs. LAP & AP = 11.11 + 0.74 LAP & 0.759 \\ ML/MAP vs. ML/AP & ML/MAP = 0.35 + 0.66 ML/AP & 0.730 \\ MAP vs. TEA & MAP = 17.82 + 0.54 TEA & 0.716 \\ LAP vs. TEA & LAP = 17.74 + 0.58 TEA & 0.709 \\ ML/LAP vs. ML/AP & ML/LAP = 0.37 + 0.60 ML/AP & 0.705 \\ LPC vs. MPC & LPC = 16.39 + 0.56 MC & 0.702 \\ AP vs. TEA & AP = 13.68 + 0.54 TEA & 0.692 \\ AP vs. ML/AP & AP = 102.10 \(-\) 33.55 ML/AP & 0.636 \\ LAP vs. ML/LAP & LAP = 109.00 \(-\) 37.61 ML/LAP & 0.588 \\ ML vs. MCW & ML = 44.29 + 0.94 MCW & 0.586 \\ MAP vs. ML/AP & MAP = 101.60 \(-\) 29.84 ML/AP & 0.584 \\ MCW vs. TEA & TEA = 53.30 + 1.15 MCW & 0.575 \\ \hline \hline \end{tabular}
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Table 6: The equations for the high pairwise correlation of Thai male morphometric parameters. \begin{table}
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**Parameters** & **Linear Regression Equation** & **Correlation** \\  & & **Coefficient (r)** \\ \hline AP vs. MAP & AP = 3.24 + 0.87 MAP & 0.931 \\ LPC vs. MPC & LPC = 8.68 + 0.72 MPC & 0.802 \\ LAP vs. TEA & LAP = 10.96 + 0.66 TEA & 0.778 \\ LPC vs. LAP & LPC = 2.67 + 0.54 LAP & 0.711 \\ MPC vs. LAP & MPC = 2.18 + 0.58 LAP & 0.680 \\ ML vs. TEA & ML = 16.48 + 0.68 TEA & 0.664 \\ TEA vs. MPC & TEA = 40.42 + 0.92 MPC & 0.661 \\ LPC vs. TEA & LPC = 4.17 + 0.42 TEA & 0.646 \\ AP vs. ML/AP & AP = 88.06 \(-\) 27.64 ML/AP & 0.645 \\ LAP vs. AP & LAP = 30.40 + 0.55 AP & 0.630 \\ MCW vs. LAP & MCW = 4.00 + 0.33 LAP & 0.621 \\ ML/LAP vs. ML/AP & ML/LAP = 0.50 + 0.49 ML/AP & 0.619 \\ LPC vs. MCW & LPC = 14.96 + 0.85 MCW & 0.592 \\ MAP vs. LAP & MAP = 14.84 + 0.70 LAP & 0.583 \\ ML vs. ML/LAP & ML = 29.52 + 33.40 ML/LAP & 0.576 \\ \hline \hline \end{tabular}
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Table 7: The equations for the high pairwise correlation of Thai female morphometric parameters. prosthetic selection, precise sizing, and proper placement of the components. Two variables used to select the femoral implant sizing are anteroposterior width (AP) and mediolateral length (ML). Thus, a mismatch analysis between these variables and the femoral component sizing that is commonly used in Thailand including the DEPUY (Sigma), ZIMMER (Nexgen), SMITH & NEPHEW (Genesis II), and STRYKER (Scorpio) [34] was evaluated. The correlation between anatomical and implant dimension was analyzed and is shown in Figure 4. The result was that the size distribution of four implants at the same anteroposterior width appears to undersize the mediolateral length of Thais. To improve the design of knee prostheses for Thais, the size of the femoral component, particularly mediolateral length, should be improved. To determine the optimum size of the femoral component, the correlation between the femoral mediolateral length (ML) and the medial anteroposterior width (AP) shown in Figure 4 was classified as femoral component size for Thais by K-means clustering analysis. In this study, the number of clusters was evaluated with variations from three to 12 clusters, finding the cluster centroid for each group. To determine the optimal numbers of the cluster, the total within-cluster sum of squares (WSS) for each cluster was computed. Then, the WSS according to the number of clusters were plotted as curves, as shown in Figure 5. The location of a bend in the graph is generally regarded as an indicator of the number of appropriate clusters [35].