The results demonstrated that preoperative anxiety [odds ratio (OR) = 2.689; 95% confidence interval (CI) = 1.355-5.338; P = 0.005], preoperative depression (OR = 3.453; 95%CI = 1.733-6.882; P < 0.001), preoperative pain VAS score (left side) (OR = 2.368; 95%CI = 1.218-4.608; P = 0.011), duration of use of tourniquet (OR = 1.060; 95%CI = 1.018-1.105; P = 0.005), pain VAS score at discharge (OR = 2.310; 95%CI = 1.165-4.580; P = 0.017), and CRP one day after surgery (OR = 1.306; 95%CI = 1.003-1.070; P = 0.031) were all significant predictors of CPSP. Here, CRP is linked to major depressive disorder.