Background: Venous thromboembolism (VTE) is a common and potential serious complication in lower extremity surgeries, especially in hip and knee arthroplasty. Pulmonary embolism is one of the most fatal complications. The recognition of VTE in the lower limb has been considered as an indication for anticoagulation. Many studies have shown that thrombophilia is one factor of VTE and the most common causes are protein C, protein S and antithrombin III deficiency, factor V leiden and dysfibrinogenemia. VTE is a disease of Western populations because of well documentation of incidence and many studies about thrombophilia. In Thailand, the prevalence of VTE has been unclear.
Objective: The present prospective study evaluated the prevalence of thrombophilia and venous thromboembolism after total knee arthroplasty in patients who did not receive prophylactic treatment of VTE in Phramongkutklao Hospital.
Study design: Descriptive prospective consecutive case studies.
Setting: The Department of Orthopedic Surgery, Phramongkutklao Hospital, Bangkok Thailand.
Material and Method: Blood sample was examined at 2-3 weeks before TKA for measuring the level of thrombophilia. Bilateral ascending contrast venography of the lower extremities was performed routinely between 6th-10th post operative days after total knee arthroplasty.
Results: The authors studied 100 patients, 94 primary TKA and 6 revisions TKA. Sixty-one (61%) were positive for deep vein thrombosis. Eleven patients with positive venograms showed bilateral DVT, twelve (12%) had a proximal DVT, one was protein C deficiency, nine were protein S deficiency, 18 were antithrombin III deficiency, and 36 were positive study for FDP(D-dimer), However, no one was found with factor V leiden. Odds ratio of protein S deficiency was 0.9506, Antithrombin III deficiency was 0.7376, and FDP(Ddimer) was 1.229. The protein C deficiency and factor V leiden was undetermined.
Conclusion: Patients who have total knee arthroplasty performed are at high risk for deep venous thrombosis. Although fetal pulmonary embolism rarely occurs in Thai populations, mechanical prevention was routinely used and prophylactic regimen should be a part of management of patients who undergo total knee arthroplasty.

Keywords: Thrombophilia, Venous thromboembolism, Total knee arthroplasty