Significance of D-Dimer Levels in the Evaluation of Postoperative Muscular Calf Vein Thrombosis: A Restricted Cubic Spline Analysis.

BackgroundD-dimer have been frequently used to assess the preliminary risk of muscular calf vein thrombosis (MCVT) after knee arthroplasty. However, D-dimer is usually higher than the clinical reference range in clinical settings, the relationship between D-dimer and postoperative MCVT remains to be explored.ObjectiveTo investigate the association between postoperative MCVT and D-dimer after knee arthroplasty.MethodsA retrospective case-control study was conducted on patients who received knee arthroplasty in the Department of Orthopaedics from September 1, 2022, to December 31, 2022.We collected basic demographic information, disease history, surgical and anesthesia information, blood examination results on admission and the first day of postoperative, and postoperative MCVT from patients. A multivariate logistic regression model was adopted to evaluate the association between D-dimer and postoperative MCVT, and the restricted cubic spline was used to analyze the dose-response relationship between D-dimer and postoperative MCVT.ResultsPostoperative MCVT was diagnosed in 103 out of 401 patients, with a prevalence of 25.69%. The median of preoperative and postoperative D-dimer was 0.47 ug/mL and 3.80 ug/mL in patients with postoperative MCVT, compared with 0.42 ug/mL and 2.42 ug/mL in patients without postoperative MCVT. After adjustment for the covariates, postoperative D-dimer was statistically significantly associated with an increased risk of postoperative MCVT. Restricted cubic spline regression showed a nonlinear dose-response relationship between postoperative D-dimer and postoperative MCVT and an increased risk of postoperative MCVT overall with higher D-dimer levels when D-dimer was over 2.62 ug/mL. There was no interaction between D-dimer and postoperative MCVT for the subgroups of age, sex, lacunar cerebral infarction, nerve block anesthesia, and surgery duration in the subgroup analyses.ConclusionsWith the high incidence of postoperative MCVT in patients with knee arthroplasty and the positive dose-response relationship between postoperative D-dimer and the risk of postoperative MCVT, risk stratification strategies should be developed for postoperative D-dimer to reduce the incidence of postoperative MCVT in patients with knee arthroplasty.