## 3 Results
### Indirect Signs of ACL Graft Insufficiency
#### 3.2.3 Anterior Tibia Subluxation
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{6}{c}{**PCL Subluxation**} \\ \cline{3-8}  & & **Me** & **LI** & **UI** & **Me** & **LI** & **UI** \\ \hline \multirow{8}{*}{\(\beta\)} & Intercept & \(-0.73\) & \(-1.67\) & \(0.18\) & \(-0.64\) & \(-1.66\) & \(0.36\) \\  & Week [L] & **3.58** & **2.43** & **4.73** & **3.52** & **2.3** & **4.74** \\  & Week [Q] & \(-0.86\) & \(-1.93\) & \(0.25\) & \(-1.01\) & \(-2.07\) & \(0.04\) \\  & SNQ & **1.03** & **0.51** & **1.6** & **1.12** & **0.6** & **1.67** \\  & SD & 0.18 & \(-0.28\) & \(0.64\) & \(-0.33\) & \(-0.79\) & \(0.11\) \\  & Sex & \(-0.4\) & \(-1.23\) & \(0.42\) & \(-0.48\) & \(-1.34\) & \(0.34\) \\  & Age & \(-0.29\) & \(-1.1\) & \(0.56\) & \(-0.35\) & \(-1.23\) & \(0.55\) \\  & Weight bearing & 0.24 & \(-0.66\) & \(1.17\) & \(0.39\) & \(-0.55\) & \(1.37\) \\  & Week [L] : Sex & 0.16 & \(-0.87\) & \(1.23\) & \(0.02\) & \(-1\) & \(1.1\) \\  & Week [Q] : Sex & 0.74 & \(-0.2\) & \(1.74\) & \(0.7\) & \(-0.26\) & \(1.71\) \\  & Week [L] : Age & \(-0.32\) & \(-1.37\) & \(0.71\) & \(-0.2\) & \(-1.3\) & \(0.92\) \\  & Week [Q] : Age & **1.11** & **0.14** & **2.14** & **1.2** & **0.15** & **2.23** \\  & Week [L] : Weight bearing & \(-0.25\) & \(-1.34\) & \(0.83\) & \(-0.1\) & \(-1.16\) & \(1.06\) \\  & Week [Q] : Weight bearing & 0.4 & \(-0.63\) & \(1.41\) & \(0.32\) & \(-0.76\) & \(1.39\) \\ \hline \(\tau\) & \(\beta\) Intercept & 2.64 & 1.84 & 3.69 & 2.86 & 2.01 & 3.88 \\ \hline \multicolumn{2}{c}{Model accuracy} & \multicolumn{2}{c}{0.89} & \multicolumn{2}{c}{0.89} \\ \hline \hline \end{tabular} Note: Me is median of posterior, and LI and UI are lower and user bounds of 95% credible interval. [L] and [Q]—linear and quadratic trends. The \(\hat{\cdot}\)\(\hat{\cdot}\) symbol indicates interaction term. \(\beta\)—regression weight; \(\tau\)—patient random effect. The coefficients are on the logit scale. Statistically credible effects are bolded.  
\end{table} 
Table 5: Results of Bayesian multilevel logistic regressions with anterior tibia subluxation as the dependent variable. Model coefficients are presented in Table 6 and selected predicted posterior means of anterior tibial subluxation are presented in Figure 9.  
We observed that anterior tibia subluxation mainly increased over the course of the study. The non-linear trend of the week predictor was also statistically credible, but relatively small, which indicated a slightly lower increase of the subluxation in the last weeks of the study. The SNQ index was credibly and positively associated with subluxation, although the relationship was rather weak. The linear increase over the weeks was weakly associated to age, where increases were more apparent in younger patients. Most importantly, we observed statistically credible differences of the anterior tibia subluxation state at week 2. Average subluxation was lower among patients who started with negative subluxation. In addition, the linear increase was noticeably stronger among this group of patients, as compared to patients who had non-negative subluxation at week 2.