Deep vein thrombosis (DVT) that was not identified by ultrasound was detectable through contrast-enhanced computed tomography (CT) in patients with hemophilia A undergoing total knee arthroplasty (TKA), according to study results published in Hemophilia.

A team of researchers conducted a prospective, single-center study based in Japan to determine the prevalence of DVT after TKA among patients with hemophilia A. The analysis included 11 patients who had hemophilia A, without a history of inhibitor use, and who were undergoing TKA. Patients were evaluated by both ultrasound and contrast-enhanced CT scans.

Ultrasound of lower extremities was performed before and after surgery, with the postsurgery scans conducted on day 2 or 3 after surgery to detect DVT. CT scans were performed only after surgery, on day 7, and to detect venous thromboembolism (VTE) overall. D-dimer levels were also assessed before and after surgery.

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In no cases did ultrasound identify a DVT either before or after TKA was performed. However, contrast-enhanced CT showed DVT in 2 instances, reflecting 18% of the patients. The affected patients had DVTs on the extremity that had undergone the procedure. The patients did not demonstrate symptoms of VTE, therefore, treatment for VTE was not administered.

Patients had a mean age of 50.5 years, a mean body mass index of 23.8 kg/m2 (range, 10.1-30.1), and no prior history of VTE. Severe hemophilia was present in 6 patients, and moderate hemophilia was present in 5.

The mean preoperative D-dimer concentration was 1.7 mg/mL, and <10.0 mg/mL 2 days following surgery. Preoperative D-dimer levels did not appear to differ between patients who showed DVTs on CT scans and those who did not.

While the study investigators noted that ultrasound is more often performed to diagnose DVT, in this study it did not display the sensitivity at identifying DVT that contrast-enhanced CT did.

“In conclusion, contrast-enhanced CT detected DVT in 18% of haemophilia A patients who underwent TKA, despite no detection of DVT on [ultrasound],” wrote the study investigators in their report.

“We will have to consider how to prevent VTE and to determine the most appropriate balance between thromboembolic prophylaxis and haemostasis in patients with haemophilia undergoing orthopaedic surgery,” they concluded.


Ono K, Takedani H. Risk of deep venous thrombosis after total knee arthroplasty in patients with haemophilia A [published only July 22, 2020]. Haemophilia. doi: 10.1111/hae.14095