Wang Zhi-Wei, Wen Liang, Luan Yi-Chao, Ma De-Si, Dong Xiang, Cheng Cheng-Kung, Qu Tie-Bing
Department of Orthopaedics, Beijing Chaoyang Hospital, Capital Medical University, Beijing, China.
School of Biological Science and Medical Engineering, Beihang University, Beijing, China.
Front Bioeng Biotechnol. 2021 Apr 29;9:673275. doi: 10.3389/fbioe.2021.673275. eCollection 2021.
Kinematically aligned total knee replacements have been shown to better restore physiological kinematics than mechanical alignment and also offer good postoperative satisfaction. The purpose of this study is to evaluate the extent to which an inclined joint line in a kinematically aligned knee can alter the postoperative kinematics. A multi-body dynamic simulation was used to identify kinematic changes in the joint. To accurately compare mechanical alignment, kinematic alignment and a natural knee, a "standard" patient with neutral alignment of the lower extremities was selected for modeling from a joint database. The arthroplasty models in this study were implanted with a single conventional cruciate-retaining prosthesis. Each model was subjected to a flexion movement and the anteroposterior translation of the femoral condyles was collected for kinematic analysis. The results showed that the mechanical alignment model underwent typical paradoxical anterior translation of the femoral condyles. Incorporating an inclined joint line in the model did not prevent the paradoxical anterior translation, but a 3° varus joint line in the kinematic alignment model could reduce the peak value of this motion by about 1 mm. Moreover, the inclined joint line did not restore the motion curve back to within the range of the kinematic curve of the natural knee. The results of this study suggest that an inclined joint line, as in the kinematic alignment model, can slightly suppress paradoxical anterior translation of the femoral condyles, but cannot restore kinematic motions similar to the physiological knee. This finding implies that prostheses intended to be used for kinematic alignment should be designed to optimize knee kinematics with the intention of restoring a physiological motion curve.
运动学对齐的全膝关节置换术已被证明比机械对齐能更好地恢复生理运动学，并且术后满意度也较高。本研究的目的是评估运动学对齐膝关节中的倾斜关节线在多大程度上会改变术后运动学。采用多体动力学模拟来识别关节的运动学变化。为了准确比较机械对齐、运动学对齐和自然膝关节，从关节数据库中选择了一名下肢中立对齐的“标准”患者进行建模。本研究中的关节置换模型植入了单一传统的保留交叉韧带假体。每个模型进行屈曲运动，并收集股骨髁的前后平移用于运动学分析。结果表明，机械对齐模型出现了典型的股骨髁矛盾性前向平移。在模型中纳入倾斜关节线并不能防止矛盾性前向平移，但运动学对齐模型中3°的内翻关节线可使该运动的峰值降低约1毫米。此外，倾斜关节线并未将运动曲线恢复到自然膝关节运动曲线范围内。本研究结果表明，如运动学对齐模型中的倾斜关节线可略微抑制股骨髁的矛盾性前向平移，但无法恢复类似于生理膝关节的运动学运动。这一发现意味着，旨在用于运动学对齐的假体应设计成优化膝关节运动学，以恢复生理运动曲线。
