Has the incidence of deep vein thrombosis in patients undergoing total hip/knee arthroplasty changed over time? A systematic review of randomized controlled trials.

BACKGROUND: There is a perception in the orthopaedic and thromboembolism community that the incidence of deep vein thrombosis (DVT) has decreased in patients undergoing total knee arthroplasty (TKA) or total hip arthroplasty (THA). OBJECTIVES: To assess the incidence of DVT with warfarin thromboprophylaxis over time in patients undergoing elective TKA or THA. METHODS: The MEDLINE, EMBASE, and Cochrane Library databases were searched to October 2006, supplemented by a manual search of reference lists. Two reviewers independently extracted data on study characteristics, quality and the frequency of total, symptomatic and proximal DVT. RESULTS: Fourteen studies (4,423 patients) were included. Total and proximal DVT after TKA declined over time (r=-0.75, p=0.031; r=-0.86, p=0.007 respectively). Total and proximal DVT after THA did not change. The risk of developing DVT after TKA was significantly higher than after THA (OR 1.85, 95% CI 1.6-2.14; p<0.0001). The risk of developing symptomatic DVT after THA was significantly higher than after TKA (OR 2.18, 95% CI 1.11-4.27; p=0.012). CONCLUSIONS: The incidence of DVT in patients undergoing elective TKA appears to have declined in patients receiving warfarin thromboprophylaxis.