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.

简介 运动学对齐全膝关节置换术 (KA-TKA) 因其比机械对齐 TKA 获得更有利的临床结果而引起人们的兴趣。据报道，KA-TKA 的优点之一是易于获得术中软组织平衡，而无需过度释放内翻骨关节炎的内侧。然而，我们假设即使在 KA-TKA 中，假体类型也会影响术中软组织平衡。本研究旨在比较使用单半径 (SR) 或多半径 (MR) 假体的 KA-TKA 术中软组织平衡和临床结果。

材料 和方法使用导航系统对内翻型骨关节炎患者连续进行 70 例保留十字形的改良 KA-TKA（31 例 SR 和 39 例 MR）。使用偏移型张量在整个运动范围内通过股骨假体放置和髌股关节复位来测量术中软组织平衡，包括关节假体间隙和内翻/外翻平衡，并在两组之间进行比较。术后两年，比较两组的活动范围和 2011 年膝关节协会评分。

结果与结论 0 至 30 度屈曲时，两组之间的关节组件间隙没有显着差异。然而，在60至120度屈曲期间，SR组的关节组件间隙显着大于MR组（p  <0.05）。两组之间在整个运动范围内内翻/外翻平衡没有显着差异。术后临床结果两组间无显着差异。

解释 尽管临床结果没有差异，但由于改良 KA-TKAs 中的假体类型，关节组件间隙表现出不同的模式。