Is D-Dimer Associated With Disease Severity and Contralateral Slip Risk in Slipped Capital Femoral Epiphysis?

To evaluate D-dimer levels in patients with slipped capital femoral epiphysis (SCFE), to investigate their association with disease severity and the development of contralateral slip, and to assess their contribution to existing predictive models.

In this single-center retrospective cohort study, 25 patients with unilateral SCFE diagnosed between January 2020 and April 2024 were included. The control group consisted of age- and sex-matched obese individuals and healthy subjects with normal body mass index (BMI). Clinical variables (age, sex, BMI, stability according to the Loder classification, and chronicity); laboratory parameters [complete blood count, neutrophil-to-lymphocyte ratio (NLR), inflammatory markers including C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR), and coagulation parameters including prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen, and D-dimer]; and radiographic measurements [Southwick angle, interhip angle difference, posterior sloping angle (PSA), and modified Oxford bone score (MOBS)] were analyzed. Subgroup analyses based on stability and chronicity were performed, and correlations between D-dimer levels and clinical, laboratory, and radiographic parameters were assessed. Multivariable logistic regression models were constructed to predict contralateral slip, and model performance was evaluated using receiver operating characteristic (ROC) curve analysis.

D-dimer levels were significantly higher in the SCFE group compared with both obese and healthy control groups (P<0.001). D-dimer showed positive correlations with CRP and NLR and negative correlations with the MOBS and the interhip Southwick angle difference. Higher D-dimer levels were observed in unstable and acute-on-chronic cases (P<0.001). During a mean follow-up of 24 months, patients who developed contralateral slip had significantly higher D-dimer levels (P=0.002). The addition of Southwick angle difference to a baseline model including age and MOBS increased the AUC from 0.73 to 0.80, while further inclusion of D-dimer improved the AUC to 0.87. However, the increase in AUC after addition of D-dimer was not statistically significant according to the paired DeLong test (P=0.18).

D-dimer levels are associated with disease severity and the risk of contralateral slip in SCFE. Incorporation of D-dimer into established clinical and radiographic parameters improved predictive model performance. These findings support the role of inflammatory and microvascular processes in the pathogenesis of SCFE and suggest that D-dimer may serve as a useful adjunct biomarker for risk stratification.

Level III-retrospective cohort study.