"Spontaneous" Heparin-Induced Thrombocytopenia and Thrombosis After Total Knee Arthroplasty: A Report of 2 Cases.

"Spontaneous" heparin-induced thrombocytopenia is a rare and virulent form of heparin-induced thrombocytopenia that occurs in the absence of exposure to any drug of the heparin class of anticoagulants. Most reported cases have occurred after knee replacement surgery. Herein we report 2 additional cases following total knee replacement. Clinical suspicion and immediate initiation of appropriate nonheparin anticoagulation are essential to avoid potentially devastating thrombotic complications.