Venous thromboembolism following primary total knee arthroplasty

Aim. Total knee arthroplasty is associated with a high postoperative incidence of venous thromboembolism (VTE). Without thromboprophylaxis, as many as 80% of patients may develop deep vein thrombosis (DVT). Evidence suggests that pharmacological prophylaxis may not be offered due to concern of bleeding with anticoagulants. Methods. We retrospectively reviewed the clinical incidence of VTE and thromboprophylactic practice patterns over a 9-year period. Patient baseline characteristics, diagnosis, VTE risk factors, prophylactic modalities (mechanical and pharmacological), operation duration, type of prosthesis and fixation, mode of anesthesia, hospital length of stay (LOS) and postoperative complications with particular attention to suspected DVT and/or pulmonary embolism (PE) were analysed. Results. Male to female ratio was 1:2.3, median age 71 (interquartile range, IQR: 65-77) years and hospital LOS of 8 (IQR.: 7-11) days. The in-hospital VTE incidence was 3.9% (95% confidence interval, Cl: 2.2-6.8%) with a possibly underestimated 3-month rate of 5.7% (95% CI: 1.6-18.6%). In-hospital proximal DVT incidence was 0.7% (95% CI: 0.22.5%) and 2.9% (95% Cl: 0.5-14.5%) at 3 months. Non fatal PE was 0.7% (95% Cl: 1.2-5%). DVT rate was higher with cemented prostheses (P=0.008), with a greater rate of bleeding when heparin was commenced preoperatively (P=0.001). Conclusions. The rate of in-hospital VTE was kept relativety low with the use of prophylactic protocols with all patients receiving prophylaxis. Given our one and a half and four-fold increase in the out of hospital VTE and proximal DVT incidence, consideration should be given to continued prophylaxis beyond hospitalization in this high-risk group of patients.