## 3 Results  
The results obtained from all groups are summarized in Table 2. The varus FTA group had a significantly higher proportion of trochoid-type PTFJs (23 (53.5%)) than the other groups (\(\chi 2(3)=15.305\), \(p=0.021\)), whereas the predominant shape in the valgus FTA group (5 (50.0%)) and normal FTA group (7 (50.0%)) was a plane-type PTFJ. The inclination angle in the varus group was significantly more oblique (39.64 (SD: 3.21)) than the valgus group (36.32 (SD: 4.94)) and normal group (32.28 (SD: 5.92)) (\(p\)= 0.025). The PTFJ was significantly closer to the tibia in the valgus group (0.25 (SD: 0.01)) than in the varus group (0.28 (SD: 0.10)) and normal group (0.30 (SD: 0.03)) (\(p\) = 0.019). The PTFJ in the valgus group (22.82 (SD: 1.99)) was significantly more likely to be located anteriorly than the varus group (24.12 (SD: 5.62)) and normal group (24.93 (SD: 2.14)) (\(p\) = 0.011). There were no significant differences between the three groups in terms of articular surface area (\(p\) = 0.688).  
The results of the multiple logistic regression model suggest that some PTFJ morphological features were statistically related to knee alignment (\(\chi^{2}(5)=16.291\), \(p=0.029\) for the unadjusted model; \(\chi^{2}\) (5) = 20.817, \(p=0.020\) for the adjusted model). Correlations between each joint characteristic and the FTA groups are shown in Table 3. These results indicate that a higher relative articular height is related to a higher possibility of having a valgus knee (OR: 0.547, 95% CI: 0.129-0.831, \(p=0.034\)) than a varus knee, even when adjusted for age, sex, and BMI (OR: 0.608, 95% CI: 0.205-0.998, \(p=0.017\)). Similarly, a smaller declination angle was also significantly associated with a greater likelihood of exhibiting a valgus knee (unadjusted model: OR: 0.307, 95% CI: 0.095-0.759, \(p=0.020\); adjusted model: OR: 0.632, 95% CI: 0.601-0.887, \(p=0.019\)) than a varus knee, which indicated that the more anterior the fibula head relative to tibia platform center, the more likely one had a valgus deformity. We also found that the shape type, PTFJ surface area, and inclination angle were not significantly correlated with different knee alignment groups. Furthermore, the PTFJ morphology was not significantly correlated with the presence of a varus knee or a normal knee. Compared with the varus FTA group, the normal FTA group regression  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Normal FTA**} & \multicolumn{2}{c}{**Varus FTA**} & \multicolumn{2}{c}{**Valgus FTA**} & \multicolumn{2}{c}{**P (Normal FTA,**} \\  & **(\(\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf{\mathbf\mathbf{}}}}}}}}}}}}}}}}\)\) & & (\(\)\(\)\(\)\(\chi^{2}(5)=16.291\), \(p=0.029\), \(p=0.029\), \(p=0.02  
value for shape type was OR: 1.327, 95% CI: 0.592-1.402, \(p\) = 0.336; the articular surface area was OR: 1.832, 95% CI: 1.781-1.923, \(p\) = 0.782; the inclination of PTFJ was OR: 0.317, 95% CI: 0.245-0.423, \(p\) = 0.019; the relative articular height was OR: 0.828, 95% CI: 0.681-0.952, \(p\) = 0.092; and the declination of PTFJ was OR: 1.506, 95% CI: 1.362-1.759, \(p\) = 0.083 in the unadjusted model. The results in the adjusted model were consistent with those from the unadjusted regression model.