## 3 Results  
There were differences in demographics and NLR between the OA patients (111) and healthy controls: age 59.3 versus 42.4 years old (\(p<0.001\)); M:F ratio 1:2.58 versus 1:5.2 (\(p<0.001\)); average NLR 2.33 versus 1.98 (\(p=0.007\)). Subgroup analysis between the mild and advanced OA cases is presented in Table 1, Figure 1. Medium values obtained are analyzed in comparison with the normal values from literature. EuroQol EQ5D5L Index normal values--using the UK tariff range -0.285 to 1, with negative values for health states worse than death, 0 deaths and 1 best health state possible [16]. VAS normal values were considered in the range 0-100, with 100 representing best health state imaginable [15]. IKDC (International Knee Documentation Committee--subjective knee form): range 0-100, with 100 representing no impairment [15]; KOOSJR (Knee disability and Osteoarthritis Outcome Score for Joint Replacement): raw score range 0-28, with 28 representing total knee disability [14]; Neutrophil to lymphocyte ratio (NLR): normal mean value 1.65 (1.96 SD: 0.78-3.53) (95% CI [0.75-0.81] and [3.40-3.66]) [19]. Patients with more advanced disease had higher NLRs. The NLR of the mild OA group was comparable to that of the controls (\(p=0.875\)), whereas the advanced OA group NLR was significantly higher (\(p=0.002\)). In the multiple regression model, NLR of patients with mild and advanced knee degeneration was only influenced by age (Table 2). \begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Mild OA (n = 66)** & **Advanced OA (n = 45)** & \(p\) \\ \hline NLR & 1.999 & 2.821 & 0.004 \\ Age & 54.06 & 67.11 & \textless{}0.001 \\ M:F ratio & 1:1.75 & 1:5.43 & 0.011 \\ Index & 0.505 & 0.253 & \textless{}0.001 \\ VAS & 64.92 & 43.88 & \textless{}0.001 \\ IKDC & 31.66 & 20.24 & \textless{}0.001 \\ KOOSJR & 1.45 & 18.33 & \textless{}0.001 \\ Kellgren-Lawrence & 1.3 & 3.8 & \textless{}0.001 \\ \hline \hline \end{tabular} Subgroup analysis of the patients with early versus advanced OA: n: number of subjects; Index: higher values indicate better health; VAS: higher values indicate better health; IKDC: higher values indicate better health; KOOSJR: lower values indicate better health.  
\end{table} 
Table 1: Demographics and clinical disease severity between the mild and severe OA groups. Figure 1: (a) Mild OA subgroup linear regression IKDC versus NLR. (b) Mild OA subgroup analysis linear regression KOOSJR versus NLR. We studied the homoscedasticity (using the Bartlett test) and the normality (using the Shapiro-Wilk test). We obtained some bad results. The Bartlett test (values from the R soft are: Bartlett's K-squared = 9.0238, _df_ = 2, p-value = 0.01098), results which rejects the null hypothesis of homoscedasticity. For the Shapiro-Wilk test (W = 0.90245, _p_-value = 7.79 \(\times 10^{-5}\)) we found the same decision, i.e., reject the hypothesis of normality. These results are based on the high variability of nonoperated patients. In the subgroup analysis, for the mild OA cases, NLR was significantly dependent to VAS, IKDC and KOOSJR (Table 2). For the advanced disease cases, NLR was only influenced by age (Table 3, Figure 2). We also studied the homoscedasticity of the advanced OA group (using the Bartlett test) and the normality (using Shapiro-Wilk test). We obtained good result for this group. The Bartlett test (with the following results from R software: Bartlett's K-squared = 0.054705, _df_ = 2, _p_-value = 0.973) which states that we cannot reject the null hypothesis of homoscedasticity. The Shapiro test (W = 0.97344, _p_-value = 0.3834) suggests that we cannot reject the normal distribution. These good results for both tests are due to the fact that after the operation the values are strongly comparable.