Preoperative Prevalence and Risk Factors For Calf Muscular Vein Thrombosis in Elderly Patients with Hip Fracture.

Objective: Increasing evidence has shown that calf muscular vein thrombosis (CMVT) can develop into proximal deep vein thrombosis, even causing pulmonary embolism. However, opinions about the prevalence and risk factors are still controversial. This study aimed to investigate the prevalence and risk factors for CMVT in elderly patients with hip fractures to facilitate their preoperative management.

Methods: We included 419 elderly patients with hip fracture who were treated in the orthopaedic department of our hospital from June 2017 to December 2020. The patients were divided into CMVT and non-CMVT groups based on color Doppler ultrasound screening of the venous system in the lower extremities. Clinical data, such as age, sex, body mass index, time from injury to admission, and laboratory data were collected. Univariate and multivariate logistic regression analyses were performed to determine independent risk factors for CMVT. A receiver operating characteristic curve was used to analyze the predictive effectiveness of the model. Finally, the clinical utility of the model was analyzed using decision curve analysis and clinical impact curves.

Results: The prevalence of preoperative CMVT was 30.5% (128/419). Independent predictors of preoperative CMVT identified by univariate and multivariate logistic regression analyses were sex, time from injury to admission, American Society of Anesthesiologists (ASA) classification, C-reactive protein (CRP) level, and D-dimer level (p < 0.05). The area under curve (AUC) was 0.750 (95% CI: 0.699-0.800, p < 0.001) and the sensitivity and specificity were 0.698 and 0.711, respectively, which meant the prediction model has a good efficacy in the prediction of CMVT risk. In addition, the fitting degree of the prediction model was also good (Hosmer-Lemeshow χ  = 8.447, p > 0.05). The clinical utility of the model was verified using decision curve analysis and clinical impact curves.

Conclusion: Sex, time from injury to admission, ASA classification, CRP level, and D-dimer levels are independent preoperative predictors of CMVT in elderly patients with hip fractures. Measures should be taken for patients with these risk factors to prevent the occurrence and deterioration of CMVT.