Prolonged Thromboprophylaxis With Dalteparin After Surgical Treatment of Achilles Tendon Rupture: A Randomized, Placebo-Controlled Study

OBJECTIVES: Prophylaxis against thromboembolic complications has become routine after major orthopedic surgery. In contrast, it remains an issue for debate whether prophylaxis after minor surgery and immobilization is necessary, even though these treatments are well-known risk factors for deep-vein thrombosis (DVT). The objective of this study was to evaluate the efficacy of dalteparin during lower-limb immobilization after surgical treatment of Achilles tendon rupture. DESIGN SETTING, AND PATIENTS: Randomized, placebo-controlled, double-blind study of 105 consecutive patients surgically treated for Achilles tendon rupture in a trauma hospital. DVT screening with color duplex sonography was conducted 3 weeks and 6 weeks after surgery. All DVTs were confirmed with phlebography. Intervention was placebo or dalteparin (5000 U) given subcutaneously once daily for 6 weeks postoperatively. MAIN OUTCOME MEASURE: DVT incidence. RESULTS: Primary endpoint analysis was available for 91 patients. DVT was diagnosed in 16 of 47 patients (34%) in the dalteparin group and in 16 of 44 patients (36%) in the placebo group. These figures are not significantly different (P = 0.8). Proximal DVT was diagnosed in 1 patient (2%) in the dalteparin group and in 3 patients (6%) in the placebo group (P = 0.6). No pulmonary emboli or major bleeding occurred in either of the groups. CONCLUSIONS: DVT is common after surgical treatment of Achilles tendon rupture, and therefore effective thromboprophylaxis is desirable. In our study, thromboprophylaxis with dalteparin, however, does not affect the incidence of DVT during immobilization after Achilles tendon rupture surgery. Long-term effects of immobilization, such as the risk for postthrombotic syndrome, need to be investigated further.