Statistical analysis
Sample size calculation was performed using data from a cross-sectional study with the same coating system [Data description was based on means and standard deviation (SD) for continuous values and absolute and relative frequencies for categorical values. Comparisons between treatment groups were done by Mann-Whitney-U-Test for continuous values and chi-square test for categorical values. Differences between normal and elevated cytokine levels with regard to PROMs were also analyzed by Mann-Whitney-U-Test. Significance level was set at p < 0.05. The software SPSS (release 26 for Windows) was used for data analysis.