Improvement in primary resection accuracy with Image Free Robotic Assisted Total Knee Arthroplasty compared to Navigation

Aims: Several studies have been performed that compare the accuracy of Robotic-Assisted Total Knee Arthroplasty (RATKA) to conventional instrumentation as well as navigation to conventional instrumentation, yet there is a lack of studies comparing RATKA to navigation. The purpose of this study is to evaluate the accuracy of a contemporary image free navigation system for TKA in a cadaveric study using the same methodology as used previously to access the accuracy of a RATKA system and conventional instrumentation. Methods: Four orthopaedic surgeons performed bi-lateral TKA on 18 pelvis-to-toe cadaveric specimens without implantation using the BrainLab Knee3 navigation system. Preoperative and postoperative computed tomography (CT) scans were taken to access the resection accuracy of the navigation system relative to the planned alignment targets recorded intraoperatively. Results: The mean error in femoral coronal angle was 1.08° ± 0.87° compared to 1.39° ± 0.95° conventional and 0.63° ± 0.50° RATKA; the differences between navigation and RATKA were statistically significant. The mean error in the tibial coronal angle was 1.24° ± 1.13° compared to 1.65° ± 1.29° conventional and 0.93° ± 0.72° RATKA. The mean error in femoral flexion was 2.13° ± 1.87° compared to 3.27° ± 2.51° conventional and 1.21° ± 0.90° RATKA; the differences between navigation and manual and navigation and RATKA were statistically significant. The mean errors in the femoral rotation (navigation 1.30° ± 1.38°, conventional 1.00° ± 0.70°, RATKA 1.04° ± 0.81°) and tibial slope (navigation 1.89° ± 1.28°, conventional 1.63° ± 1.39°, RATKA 1.62° ± 1.13°) were similar between the groups. Conclusion: This study showed that for some metrics navigation improves resection accuracy compared to conventional instrumentation and RATKA further improves resection accuracy compared to CAS.