Total knee replacement in a patient with lupus anticoagulant.

The lupus anticoagulant is an acquired circulating anticoagulant that was first described in patients with systemic lupus erythematosus (SLE). This rare hematologic entity is seen in about 1% to 2% of the general population and about 10% to 35% of the patients with SLE. Although associated with a prolonged partial thromboplastin time (PTT), the lupus anticoagulant does not cause bleeding complications but may be associated with an increase in thromboembolic complications. This report is presented to alert orthopedic surgeons of the increased risk of thromboembolic disease with a paradoxically prolonged PTT in patients with the lupus anticoagulant.