Abstract
Robotic-assisted surgery (RAS) in total knee arthroplasty (TKA) is becoming popular
due to better precision, when compared with other instrumentation. Although RAS has
been validated in comparison with computer-assisted surgery (CAS), data from clinical
settings comparing these two techniques are lacking. This is especially the case for
sagittal alignment. Whereas pure mechanical alignment (MA) aims for 0 to 3 degrees
of flexion of the femoral component and 3° of posterior slope for the tibial component,
adjusted MA (aMA) mostly used with RAS allows for flexing of the femoral component
for downsizing and increase of slope for an increase of the flexion gap. In the present
study, we compared sagittal alignment after TKA using RAS with aMA and CAS targeting
MA, which has been the standard in the center for more than 10 years. We analyzed
a prospectively collected database of patients undergoing TKA in a single center.
Femoral component flexion and tibial slope were compared for both techniques. In 140
patients, 68 CAS and 72 RAS, we found no difference in tibial slope (p = 0.661), 1° median femoral component flexion (p = 0.023), and no difference in outliers (femur, p = 0.276, tibia, p = 0.289). RAS slightly increases femoral component flexion, but has no influence
on tibial slope, when compared with CAS in TKA. If MA is the target, RAS provides
no benefit over CAS for achieving the targeted sagittal alignment.
Level of Evidence Level III retrospective study.
Keywords arthroplasty - robotic - RAS
