Blood loss after minimally invasive total knee arthroplasty: effects of imageless navigation.

A prospective cohort study of 100 patients undergoing primary minimally invasive total knee arthroplasty was carried out to determine blood loss after this procedure and to examine the efficacy of navigation on blood saving. The patients were divided into two groups according to the surgical technique, and underwent either computer-assisted navigation or manual procedures. All operations were performed by a single surgeon using an identical approach. To minimize blood loss, an intraoperative tourniquet was used, but no postoperative drainage was applied. Although the mean surgical time was longer in the navigated group than in the manual group (119.2 vs. 90.9 min; p < 0.001), the reductions in hemoglobin level (1.40 vs. 1.38 g/dL; p = 0.642) and calculated blood loss (470.77 vs. 482.73 mL; p = 0.796) were similar in both groups. Four patients in both groups required blood transfusion. With minimally invasive techniques and drainage avoidance, our study suggests that the blood loss after minimally invasive total knee arthroplasty was not significantly affected by the use of imageless navigation.