Anticoagulant therapy for osteonecrosis associated with heritable hypofibrinolysis and thrombophilia

Osteonecrosis develops as the end-result of reduced blood flow to the femor al head. We postulate that venous thrombosis leads to increased intraosseus venous pressure, reduced arterial flow and hypoxic bone death. Hypofibrino lysis (reduced ability to lyse thrombi) and thrombophilia (increased tenden cy to form thrombi) appear to play an important role in osteonecrosis. If c oagulation disorders cause osteonecrosis, then anticoagulation might amelio rate osteonecrosis. In subjects with coagulation disorders and osteonecrosi s of the hip, provided that anticoagulant therapy is started before irrever sible segmental collapse of the head of the femur, osteonecrosis may be arr ested or, speculatively, sometimes reversed. This has the potential of prev enting femoral head collapse which usually leads to total hip replacement.