Effects of computer-assisted navigation versus the conventional technique for total knee arthroplasty on levels of plasma thrombotic markers: a prospective study

BACKGROUND: Venous thromboembolism (VTE) is a major sequela after total knee arthroplasty (TKA). We prospectively compared the differences in the perioperative plasma d-dimer and fibrinogen levels between the individuals undergoing TKA via computer-assisted navigation and via a conventional method as the surrogate comparison for VTE. There were 174 patients fulfilling the inclusion criteria and providing valid informed consent between September 2011 and November 2013. There were 69 females and 20 males in the navigation-assisted group (median age: 71.00 years), while the conventional group was composed of 59 females and 26 males (median age: 69.00 years). Blood samples were obtained prior to and at 24 and 72 h after surgery for measurement of the levels of plasma d-dimer and fibrinogen. RESULTS: A significantly lower plasma d-dimer level 24 h after TKA (p = 0.001) and a milder postoperative surge 24 h after TKA (p = 0.002) were observed in patients undergoing navigation-assisted TKA. The proportions of subjects exceeding the plasma d-dimer cut-off values of 7.5, 8.6 and 10 mg/L 24 h after TKA were all significantly higher in the conventional group than in the navigation-assisted group (p = 0.024, 0.004, and 0.004, respectively). CONCLUSIONS: A lower plasma d-dimer level and a milder surge in the plasma d-dimer level were observed in patients undergoing navigation-assisted TKA in comparison with patients undergoing conventional TKA 24 h after surgery. These findings may supplement the known advantages of navigation-assisted TKA.