## 3 Results
### The Clinical Characteristics of the Study Cohort in the Preoperative Period
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Parameter** & \multicolumn{2}{l}{**Median (1 st-3 rd Quantiles)**} & \multicolumn{3}{l}{_p_**-Value of Paired Wilcoxon Test**} \\ \hline  & **Pre-TKR** & **3 m after** & **12 m after** & **1 vs. 2** & **1 vs. 3** & **2 vs. 3** \\ \hline \multicolumn{5}{l}{KOOS subscales (self-assessment)} \\ \hline KOOSysmp & 29 (20–43) & 43 (26–57) & 56 (43–66) & \(7.7\times 10^{-5}\) & \(1.2\times 10^{-11}\) & \(9.5\times 10^{-7}\) \\ \hline KOOSpain & 33 (27–42) & 58 (42–69) & 64 (54–73) & \(5.1\times 10^{-9}\) & \(5.3\times 10^{-13}\) & 0.0008 \\ \hline KOOSadl & 35 (29–44) & 55 (41–65) & 64 (56–71) & \(4.0\times 10^{-8}\) & \(4.3\times 10^{-13}\) & 5.6 \(\times 10^{-5}\) \\ \hline KOOSsp/recr & 0 (0–4) & 0 (0–12) & 12 (0–25) & 0.0005 & \(4.6\times 10^{-9}\) & 0.0004 \\ \hline KOOSqol & 15 (5–20) & 28 (15–40) & 35 (20–45) & \(2.65\times 10^{-7}\) & \(9.2\times 10^{-11}\) & 0.02 \\ \hline SF-36 subscales (self-assessment) & & & & & \\ \hline SF36 PF & 25 (17–45) & 40 (30–55) & 50 (34–60) & \(3.4\times 10^{-5}\) & \(7.5\times 10^{-10}\) & 0.0022 \\ \hline SF36 RP & 0 (0–25) & 0 (0–50) & 0 (0–75) & 0.20 & 0.0025 & 0.021 \\ \hline SF36 RE & 33 (0–100) & 33 (0–100) & 67 (0–100) & 0.81 & 0.13 & 0.021 \\ \hline SF36 VT & 35 (29–45) & 40 (29–50) & 40 (30–50) & 0.15 & 0.020 & 0.63 \\ \hline SF36 MH & 40 (32–48) & 40 (32–48) & 40 (32–48) & 0.17 & 0.25 & 0.95 \\ \hline SF36 SF & 50 (25–75) & 63 (38–75) & 81 (63–100) & 0.020 & \(1.5\times 10^{-8}\) & 0.00015 \\ \hline SF36 RP & 23 (13–35) & 45 (23–58) & 45 (33–78) & \(1.2\times 10^{-6}\) & \(4.4\times 10^{-9}\) & 0.26 \\ \hline \multicolumn{5}{l}{SF36 GH} & 55 (40–65) & 60 (54–65) & 60 (49–70) & 0.081 & 0.073 & 0.35 \\ \hline \multicolumn{5}{l}{Lower limb performance tests} \\ \hline TUG (s) & 12 (10–14.5) & 11 (10–12) & 10 (8–12) & 0.051 & 0.00085 & 0.0088 \\ \hline Test-Chair (cm) & 48 (43.5–48.5) & 49.25 (40–50) & 45 (35–50) & 0.24 & 0.0018 & 0.0034 \\ \hline
30 sCST (times) & 7 (4–9) & 8 (6–11) & 9.5 (7–12) & 0.20 & 0.022 & 0.32 \\ \hline
30 mFPWT (s) & 28.5 (24.25–35) & 25 (23–30) & 24 (21–25) & 0.0042 & \(5.5\times 10^{-9}\) & 0.0002 \\ \hline \multicolumn{5}{l}{Biomarker of Coll2 degradation} \\ \hline \multicolumn{5}{l}{uC2C/Crea} & 914 (623–1179) & 947 (756–1311) & 840 (640–1069) & 0.012 & 0.54 & 0.014 \\ \hline \multicolumn{5}{l}{The Knee Injury and Osteoarthritis Outcome Score (KOOSymp), pain (KOOSpain), activities of daily living (KOOSadl), sport and recreation (KOOSsp/recr), and knee-related quality of life (KOOSqol). SF–36 subscales: physical functioning (PF); role limitations due to emotional problems (RE); energy/fatigue (VT); emotional wellbeing (MH); social functioning (SF); bodily pain (BP); general health (GH). Lower limbs performance tests: Timed Up and Go test (TUG); 30 s chair stand test (30 sCST); 30 m fast-posed walk test (30 mFPWT); the original chair test (Test-Chair).} \\ \hline \hline \end{tabular}
\end{table} 
Table 2: uC2C, KOOS, SF-36, and lower limb performance test results in the pre- and postoperative periods. These knee problems added up to a serious decline in the quality-of-life subscale (median score: 15% of maximum). SF-36 results also demonstrated a serious decline in quality-of-life aspects before the operation (Table 2). Pain and physical functioning subscales (SF36 RP, SF36 PF, and SF36 BP) were the most affected (median score < 25). At the same time, the mental and general health subscales of SF-36 had relatively high values (median scores of 40 for SF36 MH and 55 for SF36 GH). It should be noted that large intragroup variability in terms of emotional problems (SF36 RE) and social functioning (SF36 SF) was demonstrated (Figure 2). In addition to subjective complaints, we also assessed the objective function of the lower limbs in the preoperative period (Table 2). We demonstrated that walking speed assessed by 30 mFPWT dropped in the majority of kOA patients (less than 1.3 m/s in 78% of patients).