Pan X, et al. - In patients undergoing primary total knee arthroplasty (TKA), researchers analyzed the underlying connection between psychiatric comorbidities and postoperative outcomes via utilizing the National Inpatients Sample data from 2002 to 2014. It was estimated that a total of 7,153,750 patients in the United States experienced TKA between 2002 and 2014. Investigators found that depression and anxiety prevalence in TKA patients is steadily increasing every year. The outcomes of TKA were closely correlated with psychiatric disorders. In order to ensure adequate relief from postoperative pain-related symptoms and quality of life, the mental health of patients undergoing TKA needs more attention.