Incidence of fat embolism syndrome after cemented or cementless bilateral simultaneous and unilateral total knee arthroplasty.

This prospective study enrolled 100 patients undergoing unilateral total knee arthroplasty (TKA) and 100 patients undergoing bilateral simultaneous TKA. Bilateral simultaneous TKAs were done under 1 anesthesia with one side immediately following the other. To determine hemodynamic changes and to detect fat and bone marrow embolization, arterial and right atrial blood samples were obtained before insertion (baseline) and 1, 3, 5, and 10 minutes after insertion of the femoral alignment rod. Arterial and right atrial blood samples were obtained 1, 3, 5, and 10 minutes after insertion of the tibial component broach. Blood samples were obtained at 24 and 48 hours after the operation. Arterial blood pressure, heart rate, right atrial pressure, arterial oxygen tension, and carbon dioxide tension were monitored at corresponding times. The presence of fat was determined with oil red O fat stain, and the presence of cellular contents of bone marrow was determined with Wright-Giemsa stain. Fat embolism was found in 65 patients (65%) with a bilateral TKA and 46 patients (46%) with a unilateral TKA. Bone marrow cell embolism was found in 12 patients (12%) with a bilateral TKA and in 4 patients (4%) with a unilateral TKA. Six patients with positive bone marrow cells (2 patients with a unilateral TKA and 4 patients with a bilateral TKA) had neurologic manifestations.