*4.5. Statistical Analysis*

The Shapiro–Wilk's test was used to determine whether data were distributed normally. Chi-square (χ2) test or Fisher's exact test were performed to compare categorical and dichotomous data. Mann–Whitney test or unpaired *t*-test were used to compare continuous variables. Spearman's or Pearson's correlations were performed to analyze associations between continuous variables. One-way ANOVA or Kruskal–Wallis, with Tukey's post-hoc test, were used to analyze categorical data. Continuous variables were reported as median ± interquartile range (IQR), while categorical variables were reported as frequency and percentage. Generalized linear regression models were applied to investigate the association of the ACL and OA IFP variables with BMI and age. A *p* < 0.05 was considered as statistically significant. All analyses were performed with SPSS version 23.0 or R [43].
