Prevalence of fat embolism after total knee arthroplasty performed with or without computer navigation

Background: Total knee arthroplasty performed with computer-assisted navigation without breaching of the femoral medullary canal may decrease the prevalence of fat and/or bone-marrow-cell embolization. We performed this study to determine whether the use of navigation for primary total knee arthroplasty resulted in a different prevalence of fat and/or bone-marrow-cell embolization. Methods: We enrolled 160 patients (210 knees) who were scheduled to undergo primary total knee arthroplasty with navigation and 160 patients (210 knees) who were scheduled to undergo primary total knee arthroplasty without navigation. Arterial and right atrial blood samples were obtained before insertion of a femoral alignment rod or cutting of the distal part of the femur (baseline); at one, three, five, and ten minutes after insertion of an alignment rod or cutting of the distal part of the femur; before insertion of a tibial component broach (baseline); at one, three, five, and ten minutes after insertion of a tibial component broach; and at twenty-four and forty-eight hours after the operation. We determined the presence of fat emboli and bone-marrow-cell emboli in histologic preparations of the blood samples. Results: The prevalence of fat embolization was 49% (102 of 210 knees) in the total knee arthroplasty group managed with navigation and 52% (109 of 210 knees) in the total knee arthroplasty group managed without navigation (p = 0.2674). The prevalence of bone-marrow-cell embolization was 17% (thirty-six of 210 knees) in the group managed with navigation and 15% (thirty-one of 210 knees) in the group managed without navigation (p = 0.2591) Conclusions: The prevalence of fat and/or bone-marrow-cell embolization was not significantly different between the patients who underwent total knee arthroplasty with navigation and those who underwent it without navigation. Level of Evidence: Therapeutic Level II. See Instructions to Authors for a complete description of levels of evidence