Thrombocytopenia and Intra-cerebral Complications Associated with Low-Molecular-Weight Heparin Treatment in Patients Undergoing Total Hip Replacement: A Report of Two Cases

Abstract

The low-molecular-weight heparins are a group of agents widely used in the prevention of deep-vein thrombosis and pulmonary embolism in orthopaedic patients, especially those undergoing total joint replacement of the lower extremity. They have been in clinical use for almost twenty years and have proved to be at least as effective as other means of thrombosis prevention1. The American College of Chest Physicians has recommended them for routine use in total hip replacement for the past ten years, as an alternative to warfarin and adjusted-dose unfractionated heparin2,3. Their main advantages are that they can be used without laboratory monitoring and they have a favorable therapeutic index (less risk of bleeding compared with unfractionated heparin for a given antithrombotic effect)4. Bleeding and thrombocytopenia are, however, documented complications of the use of low-molecular-weight heparin5-9, but, to our knowledge, cerebral hemorrhages secondary to thrombocytopenia have not been reported in association with orthopaedic procedures. We report the cases of two patients who had thrombocytopenia and cerebral complications after routine treatment with low-molecular-weight heparin for thromboembolic prevention following total hip replacement. Our patients or their families were informed and consented that data concerning their cases would be submitted for publication. Case 1. A forty-six-year-old woman who weighed 55 kg had osteoarthritis of the hip secondary to developmental dysplasia. She had no history of bleeding predisposition or other medical problems, and she had never received any form of heparin. An uncemented total hip replacement was performed through a posterior approach. Postoperatively, the patient received a transfusion of two units of packed red-blood cells. An antithrombotic regimen of 40 mg of enoxaparin once daily was started six hours after surgery and was to be continued for four weeks. There were no bleeding complications in …