Comparison of the radiographic outcomes and total blood loss between pinless navigation and conventional method in minimally invasive total knee arthroplasty

Background Computer-assisted surgical navigation has been used in total knee arthroplasty (TKA) procedures for years trying to the accuracy of prosthesis placement. We conducted this prospective randomized clinical trial to compare the accuracy of the radiographic parameters of the prosthesis, total blood loss (TBL), and related complications, between a new pinless navigation system (Stryker OrthoMap Express Knee Navigation) and conventional method in patients undergoing minimally invasive (MIS) TKA procedures. Patient and methods A consecutive series of 100 patients underwent unilateral primary TKA were randomly assigned into two groups: navigation group and convention group. The radiographic parameters of the knee implant and the alignment of lower limb were measured at 3 months after surgery. TBL was calculated according to Nadler's method. The duplex ultrasonography of both lower limbs was performed in all patients to detect the presence of deep-vein thrombosis (DVT). Results Totally, 94 patients have completed the radiographic measures. Only the coronal femoral component angle in the navigation group (89.12 degrees +/- 1.83 degrees) had significant differences from that in the convention group (90.09 degrees +/- 2.18 degrees) (p = 0.022). There were no differences in the rate of outliers. The mean TBL in the navigation group was 841 +/- 267 mL, which was similar to that in the convention group at 860 +/- 266 mL (p = 0.721). Postoperative DVT risk did not differ between the two groups (2% vs. 0%, p = 0.315). Conclusion This pinless navigation TKA showed a comparable acceptable alignment compared with conventional MIS-TKA. There were no differences regarding postoperative TBL between the two groups.