## 3 Results
### MRI Evaluation of the Cartilage  
MRI evaluation of knee cartilage thickness was performed at the first and second follow-ups in all the studied patients (Figures 5 and 6, shown as an example). There were only slight statistical differences in cartilage thickness on the medial femoral and tibial condyle (MFC, MTC) between the study and control groups after a mean of 10.9 years follow-up (Table 4). Statistical differences in cartilage thickness on the MFC were observed \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  & & **Patient 1** & **Patient 2** & **Patient 3** & **Patient 4** & **Patient 5** \\ \hline \multirow{3}{*}{Gait distribution [\%]} & S & 49 & 50 & 50 & 50 & 51 \\ \cline{2-6}  & C & 51 & 50 & 50 & 50 & 49 \\ \hline \multirow{3}{*}{Standing [\%]} & S & 0 & 100 & 82.7 & 53 & 0 \\ \cline{2-6}  & C & 100 & 0 & 17.2 & 47 & 100 \\ \hline \multirow{3}{*}{PT-60 [Nm]} & Q & 42.4 & 19.4 & 8.1 & 23.1 & 17.8 \\ \cline{2-6}  & H & 1.3 & \(-\)29.7 & \(-\)10.8 & 11.2 & 6.5 \\ \hline \multirow{3}{*}{PT-180 [Nm]} & Q & 29.8 & 8.2 & \(-\)1.3 & 19.4 & 14.3 \\ \cline{2-6}  & H & 6.4 & \(-\)8.3 & 2 & 10.5 & \(-\)3.2 \\ \hline \multirow{3}{*}{PT/BW [Nm/kg]} & 60\({}^{\circ}\) & 118.0 & 113.1 & 146.2 & 136.7 & 126.4 \\ \hline \multirow{3}{*}{H/Q [Nm]} & 60\({}^{\circ}\) & 48.8 & 55.1 & 67.5 & 53.1 & 57.3 \\ \cline{2-6}  & 180\({}^{\circ}\) & 47.8 & 51.1 & 60.7 & 49.5 & 52.6 \\ \hline \multirow{3}{*}{Time to PT-60 [ms]} & S & 440 & 670 & 410 & 520 & 720 \\ \cline{2-6}  & C & 540 & 800 & 670 & 660 & 850 \\ \hline \multirow{3}{*}{Time to PT-180 [ms]} & S & 230 & 220 & 280 & 240 & 290 \\ \cline{2-6}  & C & 270 & 200 & 250 & 190 & 310 \\ \hline \multirow{3}{*}{Angle to PT-60 [deg.]} & S & 74 & 76 & 83 & 79 & 81 \\ \cline{2-6}  & C & 68 & 59 & 68 & 64 & 63 \\ \cline{2-6}  & S & 70 & 83 & 66 & 65 & 72 \\ \cline{2-6}  & C & 63 & 61 & 69 & 71 & 65 \\ \hline \multirow{3}{*}{Work fatigue-60} & S & 12.6 & 5.6 & \(-\)1.0 & \(-\)10.3 & 14.5 \\ \cline{2-6}  & C & 12 & \(-\)15.6 & 2.8 & \(-\)6.4 & 9.3 \\ \hline \multirow{3}{*}{Work fatigue-180} & S & 26.6 & 40.2 & 15.5 & 27.1 & 32.4 \\ \cline{2-6}  & C & 32 & 23.5 & 24.2 & 19.4 & 20.3 \\ \hline \end{tabular} S, study group (SA knee): C, control group (unaffected knee); PT-60, peak torque at velocity of 60\({}^{\circ}\)/s; Q, quadriceps muscle; H, hamstring (flexor) muscles; PT-180, peak torque at 180\({}^{\circ}\)/s; PT /BW, ratio of peak torque to body weight; H/Q 60, ratio of peak torque hamstring to quadriceps at 60\({}^{\circ}\)/s; H/Q 180\({}^{\circ}\), ratio of peak torque hamstring to quadriceps at 180\({}^{\circ}\)/s; Time to PT-60, time to peak torque at 60\({}^{\circ}\)/s; Time to PT-180, time to peak torque at 180\({}^{\circ}\)/s; Angle to PT-60, angle to peak torque at 60\({}^{\circ}\)/s; Angle to PT-180, angle to peak torque at 180\({}^{\circ}\)/s; Work fatigue-60, work fatigue at 60\({}^{\circ}\)/s; Work fatigue-180, work fatigue at 180\({}^{\circ}\)/s.  
\end{table} 
Table 3: Isokinetic results. between the study and control groups (2.077 mm and 2.237 mm, respectively; \(p=0.021\); Table 4). Interestingly, the articular cartilage on the MTC was slightly thicker in the SA knees than in the uninvolved side (2.478 mm vs. 2.24 mm; \(p=0.008\), Table 4). There were no significant differences in cartilage thickness in the lateral compartment of the knee at the first follow-up (Table 4). At the final follow-up, slight statistical differences in cartilage thickness were observed only on the lateral femoral cuddle. The cartilage in the SA knees was slightly thinner than that on the unaffected side (2.217 mm vs. 2.43 mm; \(p=0.041\); Table 4). There were no significant differences in cartilage thickness between the first and last follow-ups in the SA-affected knees.