Abstract
Introduction:
One of the complications occurring after total knee arthroplasty (TKA) is venous thromboembolism (VTE). The current screening techniques for VTE are venography, lower extremity vascular ultrasound, pulmonary scintigraphy, and contrast-enhanced computed tomography (CT). Although venography and lower extremity vascular ultrasound can detect deep venous thrombosis (DVT) in the lower extremities, pulmonary thrombosis poses a diagnostic problem. We performed contrast-enhanced CT screening for DVT and pulmonary embolism (PE) after TKA, and assessed the efficacy of the following prophylactics for VTE: fondaparinux, enoxaparin, and edoxaban.
Materials and Methods:
Subjects included 219 patients (260 knees) undergoing TKA at our hospital between April 2007 and November 2012. The 260 subject knees were divided as follows: group C, 31 cases in which DVT prophylactics were not used (April 2007 to October 2008); group F, 107 cases receiving fondaparinux 2.5 mg/day (July 2007 to October 2009); group ENO, 87 cases receiving enoxaparin 2000–4000 IU/day (November 2009 to October 2011); and group EDO, 35 cases receiving edoxaban 15–30 mg/day (November 2011 to November 2012). Contrast-enhanced CT images were obtained from the pulmonary apex to the foot for diagnosis of VTE. Groups were compared for incidence of symptomatic PE, asymptomatic PE, DVT-negative asymptomatic PE, DVT-positive asymptomatic PE, and DVT.
Results:
Incidence of symptomatic PE tended to be lower in group ENO than in group C (p = 0.067), but no statistically significant differences in asymptomatic PE were observed between any groups (Figure 1). DVT-negative asymptomatic PE (Figure 2) was present in 2 cases in group C (6.5%), 14 cases in group F (13.1%), 3 cases in group ENO (3.4%), and 2 cases in group EDO (5.7%) (Figure 1). Patients diagnosed with symptomatic PE presented only with mild clinical symptoms and physical findings. As a result, PE was not suspected from clinical findings alone. The diagnosis of symptomatic PE was confirmed by the presence of thrombosis in the pulmonary artery on contrast-enhanced CT (Figure 3).
Conclusion:
Asymptomatic PE is not prevented by prophylaxis after TKA. Contrast-enhanced CT screening is effective for identifying asymptomatic VTE, especially asymptomatic PE.
