There is currently limited information available on the benefits and risks of extended thromboprophylaxis after hip fracture surgery. SAVE-HIP3 was a randomised, double-blind study conducted to evaluate the efficacy and safety of extended thromboprophylaxis with the ultra-low molecular-weight heparin semuloparin compared with placebo in patients undergoing hip fracture surgery. After a seven- to ten-day open-label run-in phase with semuloparin (20 mg once daily subcutaneously, initiated post-operatively), patients were randomised to once-daily semuloparin (20 mg subcutaneously) or placebo for 19 to 23 additional days. The primary efficacy endpoint was a composite of any venous thromboembolism (VTE; any deep-vein thrombosis and non-fatal pulmonary embolism) or all-cause death until day 24 of the double-blind period. Safety parameters included major and clinically relevant non-major bleeding, laboratory data, and treatment-emergent adverse events (TEAEs). Extended thromboprophylaxis with semuloparin demonstrated a relative risk reduction of 79% in the rate of any VTE or all-cause death compared with placebo (3.9% vs 18.6%, respectively; odds ratio 0.18 (95% confidence interval 0.07 to 0.45), p < 0.001). Two patients in the semuloparin group and none in the placebo group experienced clinically relevant bleeding. TEAE rates were similar in both groups. In conclusion, the SAVE-HIP3 study results demonstrate that patients undergoing hip fracture surgery benefit from extended thromboprophylaxis.

Cite this article: Bone Joint J 2013;95-B:459–66.

Purpose: Venous thromboembolism (VTE) after major orthopaedic surgery remains an important clinical problem. Convenient, oral antithrombotic agents that are both effective and safe could improve adherence to guidelines for VTE prophylaxis. Recently, the focus has been on the development of oral agents that target a single step in the coagulation cascade and Factor Xa is a pivotal step. Rivaroxaban is an oral, direct Factor Xa inhibitor. Four international phase III trials (the RECORD programme) were undertaken to investigate the safety and efficacy of once-daily rivaroxaban for thromboprophylaxis after major orthopaedic surgery. The results of RECORD3 showed that rivaroxaban was more effective than enoxaparin 40 mg once daily after total knee replacement (TKR), with a 48% risk reduction in VTE and all cause mortality. RECORD4 was designed to determine the efficacy and safety of 10 mg rivaroxaban od compared to 30 mg bid enoxaparin after total knee replacement (TKR).

Method: This study randomized 3148 patients to either rivaroxaban (10 mg od started 6–8 hours after surgery) or enoxaparin (30 mg bid s.c. started 12–24 hours after surgery) for 10–14 days. The primary efficacy outcome was the composite of asymptomatic deep vein thrombosis (DVT) detected by mandatory, bilateral venography and symptomatic DVT, non-fatal pulmonary embolism (PE), and all-cause mortality up to day 13±4. Secondary outcomes included major VTE (composite of proximal DVT, non-fatal PE, and VTE-related death) and symptomatic VTE. Safety outcomes included on-treatment major and non-major bleeding.

Results: Rivaroxaban provided a 31% relative risk reduction in the incidence of the primary efficacy outcome when compared to enoxaparin (6.9% vs 10.1%, respectively; p=0.012). The corresponding rates for major VTE were 1.2% and 2.0%, respectively (p=0.124) and for symptomatic VTE were 0.7% and 1.2%, respectively (p=0.187). There were no significant differences in bleeding incidence observed between rivaroxaban and enoxaparin (major bleeding: 0.7% vs 0.3%, respectively, p=0.110; clinically relevant non-major bleeding: 2.6% vs 2.0%, respectively, p=0.279).

Conclusion: Rivaroxaban 10 mg od is the first oral thromboprophylactic agent to significantly reduce the incidence of VTE after TKR compared to enoxaparin 30 mg bid, with a similar, low rate of bleeding.

Thromboprophylaxis remains a controversial subject. A vast amount of epidemiological and trial data about venous thromboembolism has been published over the past 40 years. These data have been distilled and synthesised into guidelines designed to help the practitioner translate this extensive research into ‘evidence-based’ advice.

Guidelines should, in theory, benefit patient care by ensuring that every patient routinely receives the best prophylaxis; without guidelines, it is argued, patients may fail to receive treatment or be exposed to protocols which are ineffective, dangerous or expensive.

Guidelines, however, have not been welcomed or applied universally. In the United States, orthopaedic surgeons have published their concerns about the thromboprophylaxis guidelines prepared by the American College of Chest Physicians. In Britain, controversy persists with many surgeons unconvinced of the risk/benefit, cost/benefit or practicality of thromboprophylaxis. The extended remit of the recent National Institute of Clinical Excellence thromboprophylaxis guidelines has been challenged.

The reasons for this disquiet are addressed in this paper and particular emphasis is placed on how clinically-acceptable guidelines could be developed and applied.