BACKGROUND: While preventive antithrombotic therapy is a standard procedure in patients of Caucasian ethnic origin undergoing major orthopaedic surgeries, Asian populations are often thought to be “immune” from post-surgical deep vein thrombosis (DVT) 1. Primary prevention is therefore not a widely adopted practice in most Asian countries and studies to assess the rate of post-operative DVT have revealed great variations in incidence among these countries (Table 1) 2-9.OBJECTIVES:To study the incidence and cost of management of deep vein throm bosis (DVT), and to estimate the cost avoidance due to prophylactic therapy in a group of Hong Kong Chinese patients undergoing total hip replacement (THR). METHOD: All Chinese patients undergoing THR from Nov 98 to Dec 2001 at the Prince of Wales Hospital in Hong Kong were retrospectively evaluated. In those patients who developed DVT, the cost of management was estimated by identifying the total healthcare resources used. The cost avoidance of DVT by using prophylactic low-molecular-weight heparin LMWH (nandroparin calcium) was estimated by construction of a decision tree model. Sensitivity analysis was performed to examine whether the results were robust to changes in the key variables. The study was performed from the perspective of a publicly funded hospital. RESULTS: A total of 90 Chinese patients underwent THR surgery over the study period, yet detailed medical history was available for only 56 of them whose baselin characteristics were comparable (Table 2). Six had symptomatic DVT, yet only 3 were confirmed by Doppler ultrasonography . The incidence of confirmed symptomatic DVT in this group of Hong Kong Chinese was therefore 3.33%. CONCLUSION: The incidence of symptomatic DVT in the present group of Hong Kong Chinese patients after THR surgery was similar to that in the Caucasians. According to the decision-tree model, cost avoidance appears to be possible by using LMWH for prophylaxis of DVT in high-risk orthopaedic procedures. Prophylactic antithrombotic therapy should be considered for routine use in THR surgery.