Abstract
Several studies have reported better clinical outcomes following kinematically aligned
total knee arthroplasty (KA-TKA) than mechanically aligned TKA. Consistent reproduction
of a KA-TKA is aided by accurate tibial bone resections using computer navigation
systems. This study compares an accelerometer-based portable navigation system with
a conventional navigation system on tibial bone resection and clinical outcomes in
KA-TKA. This study included 60 knees of patients who underwent primary KA-TKA between
May 2015 and September 2017. They were randomly assigned to the OrthoPilot and iASSIST
groups. A tibial bone cut was performed with 3 degree varus and 7 degree posterior
slope in relation to the mechanical axis in all cases. The tibial component angle
(TCA) and posterior slope angle (PSA) were evaluated by postoperative radiography,
and those that deviated more than 2 degree were set as outliers. The clinical outcomes
were the knee range of motion (ROM) and 2011 Knee Society Score (KSS) evaluated at
1 year postoperation. The groups were compared in terms of the TCA, PSA, number of
outliers, ROM, and 2011 KSS (p < 0.05). No significant difference was observed between the groups in terms of the
mean TCA, PSA, number of outliers, ROM, and categories of the 2011 KSS (objective
knee indicators, symptoms, satisfaction, expectations, and functional activities).
Although tibial bone cuts were performed with 3 degree varus and 7 degree posterior
slope, no significant difference was observed between the OrthoPilot and iASSIST groups
in terms of the accuracy of cuts or postoperative clinical result. The iASSIST was
found to be a simple and useful navigation system for KA-TKA.
Keywords
kinematically aligned total knee arthroplasty - accelerometer-based portable navigation
- iASSIST - accuracy of tibial bone cutting - 2011 KSS
