Abstract
One of the primary aim of total knee arthroplasty (TKA) is restoration of the mechanical
axis of the lower limb. Maintenance of the mechanical axis within 3 degrees of neutral
has been shown to result in improved clinical results and implant longevity. The aim
of this study was to investigate the efficacy of this robotic-assisted system in coronal
plane component positioning in TKA. We also describe the learning curve associated
with adoption of this technology. A total of 72 total knee replacements were completed
between November 2017 and September 2018 by a single surgeon using the robotic-assisted
surgery (RAS) system. Cases were recorded from the time the study surgeon first adopted
this technology and represent the “learning curve.” Pre- and postoperative coronal
weight-bearing alignments were measured and intraoperative robotic-assisted registration
data and duration of use were collected. Of the 72 TKAs in this series, 93.3% were
corrected to the desired alignment of within 3 degrees of neutral. The knees that
were not corrected to neutral had a mean preoperative alignment of 11.57 degrees of
deformity as compared with 4.29 degrees for those that were corrected to neutral.
A learning curve effect during adoption of this new technology was not found when
analyzing RAS usage time. The RAS system produced accurate coronal alignment in TKA
in more than 93% of cases with no learning curve effect. Our study suggests that this
system is easily adopted, safe, and accurate.
Keywords
total knee arthroplasty - coronal alignment - robotic-assisted TKA
