Predictive value of perioperative hypothermia for postoperative muscular calf vein thrombosis after total knee arthroplasty: a retrospective cohort study

Abstract Objective To investigate the association between perioperative hypothermia and postoperative muscular calf vein thrombosis (MCVT) in patients undergoing total knee arthroplasty (TKA), and to evaluate the predictive performance of perioperative core temperature indicators for postoperative MCVT. Methods This retrospective cohort study included 903 patients who underwent TKA at a tertiary orthopaedic hospital in Henan Province, China, between January 1, 2023, and September 1, 2025. Postoperative MCVT was diagnosed using bilateral lower-limb Doppler ultrasound. Perioperative core temperature was recorded at predefined time points before, during, and after anaesthesia. Univariable analyses and multivariable logistic regression were performed to identify factors associated with postoperative MCVT. Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive performance of perioperative core temperature indicators. Results The study included 903 patients who underwent TKA, of whom 162 developed postoperative MCVT, corresponding to an incidence of 17.9 % . Multivariable logistic regression demonstrated that core temperature at anaesthesia induction, 1 h after anaesthesia induction, and emergence from anaesthesia were independently associated with postoperative MCVT. Coagulation-related indicators, including PT, APTT, TT, FIB, and D-dimer, were also significantly associated with postoperative MCVT. ROC analysis showed that core temperature 1 h after anaesthesia induction had the highest predictive performance among the temperature indicators, with an AUC of 0.755, sensitivity of 83.33 % , and specificity of 67.61 % . Core temperature at anaesthesia induction showed high sensitivity, with an AUC of 0.734, sensitivity of 93.21 % , and specificity of 53.58 % , while core temperature at emergence from anaesthesia showed an AUC of 0.704, sensitivity of 82.72 % , and specificity of 58.16 % . Conclusion The current analysis suggested that perioperative hypothermia was significantly associated with postoperative MCVT in patients who underwent TKA. Core temperature at anaesthesia induction, 1 h after anaesthesia induction, and emergence from anaesthesia showed predictive value for postoperative MCVT, with the 1 h post-induction temperature demonstrating the best performance. These findings provide evidence for targeted temperature monitoring and early thrombotic risk identification after TKA. Further prospective studies are needed to confirm whether maintaining perioperative normothermia can reduce postoperative MCVT.