Backgrounds

The correlation between in vivo knee kinematics and alignment has not been fully elucidated. Recently, similar or better clinical outcomes have been reported by restoration of mild varus alignment after total knee arthroplasty for preoperative varus knees. The aim of this study was to evaluate the effect of postoperative alignment on knee kinematics during a deep knee bend activity.

Methods

In vivo knee kinematics of 36 knees (25 patients) implanted with tri-condylar total knee arthroplasty were analyzed with a three dimensional model fitting approach using fluoroscopy. Under fluoroscopic surveillance, individual video frames were digitized at 30° increments from full extension to maximum flexion. Postoperative coronal and sagittal alignments were assessed using radiographs, and rotational alignment was assessed with computed tomography. Pearson correlation coefficients were calculated to determine the correlations between the alignment data and kinematic factors.

Findings

Correlation analysis showed that coronal alignment was significantly correlated with knee kinematics. The varus alignment of the limb and tibial component led to a greater axial rotation from full extension to maximum flexion and more rotated position in the mid to deep flexion range. Neither the rotational alignment of the femoral nor tibial components showed significant correlation with axial rotation from full extension to maximum flexion.

Interpretation

Varus alignment resulted in greater axial rotation, which could represent near-normal knee kinematics. The current study can be a kinematic rationale reporting similar or better clinical and functional outcomes for the total knee arthroplasty with residual varus alignment.

中文翻译：

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全膝关节置换术后的内翻对准导致深膝弯曲活动期间更大的轴向旋转。

背景资料

体内膝关节运动学和对准之间的相关性尚未完全阐明。最近，通过术前内翻膝关节全膝关节置换术后轻度内翻对准的恢复，已报告了相似或更好的临床结果。这项研究的目的是评估深膝弯曲活动期间术后对准对膝关节运动学的影响。

方法

使用荧光透视法，通过三维模型拟合方法分析了36例膝关节（25例患者）的植入三total全膝关节置换术的体内膝关节运动学。在荧光透视监视下，单个视频帧以从完全伸展到最大屈曲的30°增量数字化。术后用放射线照片评估冠状和矢状位，并用计算机断层摄影术评估旋转位。计算皮尔逊相关系数，以确定比对数据与运动学因素之间的相关性。

发现

相关分析表明，冠状位与膝关节运动学显着相关。肢体和胫骨组件的内翻对准导致从完全伸展到最大屈曲的更大的轴向旋转，并在中屈屈深度范围内产生了更大的旋转位置。股骨和胫骨组件的旋转对准均未显示与从完全伸展到最大屈曲的轴向旋转显着相关。

解释

内翻对准导致更大的轴向旋转，这可能代表了接近正常的膝关节运动学。当前的研究可能是运动学原理，其报告了残余内翻对准的全膝关节置换术具有相似或更佳的临床和功能结果。