The final RCT evaluated tinzaparin (yet another European LMWH) in 300 adult outpatients immobilized in plaster for at least 3 weeks. Most patients (205 out of 300) underwent venography, and the overall DVT rate was 10% (tinzaparin) vs 17% (controls). Among the 150 fracture patients who underwent venography, the DVT rate was 11% (tinzaparin) vs 13% (controls). This difference was not significant, probably due to insufficient numbers. None of the DVTs was clinically detectable.6
In hip fracture and hip arthroplasty, warfarin and LMWH are both effective in preventing thrombosis. No studies have specifically evaluated warfarin prophylaxis in lower extremity fractures or compared it with LMWH.
Recommendations from others
The American College of Chest Physicians (ACCP) says that LMWH prophylaxis reduces the risk of asymptomatic DVTs and is standard of care in Europe. The ACCP does not recommend thromboprophylaxis for isolated lower extremity fractures in the US because of cost and insufficient evidence of clinically important reduction in venous thromboembolism (VTE). However, ACCP lists unspecified “lower extremity or pelvic fracture” as a risk factor for VTE, and does recommend that trauma patients with at least 1 risk factor for VTE receive thromboprophylaxis. They make no recommendation about the use of warfarin.7
Cinical Commentary
Although LMWH costs more than daily warfarin, it has fewer complications
Dana Nadalo, MHS, PA-C
Patricia Janki, MD, PA
Houston, Tex
LMWH has largely replaced warfarin for DVT prevention in lower extremity fractures in our clinic. Subsequently, screening for warfarin’s drug-drug interactions and measuring the PT/INR levels to adjust patient doses are no longer needed. LMHW provides effective DVT prevention without laboratory monitoring. Even though LMWH costs significantly more than daily warfarin, the complications associated with warfarin use, or no prophylaxis therapy at all, could be substantially greater. We do not typically use prophylactic anticoagulation on ankle fractures, but we do routinely put high-risk patients with tibia, fibula, and femur fractures on aspirin and LMWH. In our experience, we have not had a patient develop a DVT while on LMWH prophylaxis.