Abstract
Introduction Kinematically aligned total knee arthroplasty (KA-TKA) has gained interest for achieving
more favorable clinical outcomes than mechanically aligned TKA. One of the advantages
of KA-TKA is reported to be an easy acquisition of intraoperative soft-tissue balance
without excessive medial release for varus osteoarthritis. However, we hypothesized
that the prosthesis type affects intraoperative soft-tissue balance even in the KA-TKA.
The present study aimed to compare intraoperative soft-tissue balance and clinical
outcomes of KA-TKAs using single-radius (SR) or multiradius (MR) prostheses.
Materials and Methods Consecutive 70 cruciate-retaining modified KA-TKAs (31 SR and 39 MR) were performed
in patients with varus-type osteoarthritis using a navigation system. Intraoperative
soft-tissue balance including joint component gap and varus/valgus balance was measured
with femoral component placement and patellofemoral joint reduction throughout the
range of motion using offset-type tensor and compared between the two groups. Two
years postoperatively, the range of motion and 2011 Knee Society Scores were compared
between the two groups.
Results and Conclusion Joint component gaps showed no significant differences between the two groups from
0 to 30 degrees of flexion. However, during 60 to 120 degrees of flexion, joint component
gaps of SR group showed significantly larger values than those of MR group (p < 0.05). There were no significant differences in varus/valgus balance throughout
the range of motion between the two groups. The postoperative clinical outcomes showed
no significant differences between the two groups.
Interpretation Despite no difference in clinical outcomes, joint component gap showed different
patterns due to the prosthesis type in modified KA-TKAs.
Keywords total knee arthroplasty - soft-tissue balance - kinematic alignment - single radius
- multiradius
