Symmetrical cruciate-retaining versus medial pivot prostheses: The effect of intercondylar sagittal conformity on knee kinematics and contact mechanics
Symmetrical cruciate-retaining versus medial pivot prostheses: The effect of intercondylar sagittal conformity on knee kinematics and contact mechanics
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DOI：
10.1016/j.compbiomed.2019.03.005
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发表时间：
2019-05-01
影响因子：
7.7
通讯作者：
Sugita, Naohiko
中科院分区：
文献类型：
--
作者：
Shu, Liming;Yamamoto, Ko;Sugita, Naohiko
背景：全膝关节置换术应该恢复膝关节的机械功能，使患者能够进行所需的日常活动。关节运动学和接触力学性能是决定全膝关节置换术成败的重要因素。方法：采用显式动力有限元方法，研究了约束十字保持法、非约束法和内枢法在步态、下蹲、下楼梯和爬楼梯过程中的性能差异。通过步态周期的体外实验对预测的运动学结果进行了验证。结果：结果证实，内枢轴的设计改善了运动学行为，没有矛盾的前移，这在四种活动中都存在于无约束假肢中。然而，在步态(3.9度)、下楼梯(2.2度)和爬楼梯(3.6度)过程中，发现股骨内旋转较小，这可能会导致前外侧疼痛。内侧枢轴假体内侧接触面积增大，峰值接触压力降低。相反，在内枢轴假体的外侧，接触面积和峰值接触压力与无约束假体的接触面积和峰值接触压力相等，这可能会导致磨损。结论尽管内枢轴假体提供的运动学与胫股运动的平均测量值相似，但仍需对股骨内旋转和外侧高接触压力进行进一步的活体分析和长期研究。
Background: A total knee arthroplasty should restore the mechanical function of the knee and enable patients to perform desired daily activities. The joint kinematics and contact mechanics performance are important determinants of the success of total knee arthroplasty devices. The purpose of this study was to determine the effect of intercondylar sagittal conformity on kinematics and contact mechanics.Methods: An explicit dynamic finite element method was used to investigate the differences in the performances of constrained cruciate-retaining (CR), unconstrained CR, and medial pivot designs during gait, squatting, descending stairs, and climbing stairs. The predicted kinematic results were verified through an in vitro experiment during the gait cycle.Results: The results confirmed that the medial pivot design improved the kinematic behavior with no paradoxical anterior motion, which was found in the unconstrained prosthesis during the four activities. However, a small femoral internal rotation was found during gait (3.9 degrees), descending stairs (2.2 degrees), and climbing stairs (3.6 degrees), which may produce anterolateral pain. An enlarged contact area and a lower peak contact pressure were observed on the medial side of the medial pivot prosthesis. Conversely, on the lateral side of the medial pivot prosthesis, the contact area and peak contact pressure were equal to those of the unconstrained prosthesis, which could potentially result in wear.Conclusion In summary, although the medial pivot prosthesis may provide qualitatively similar kinematics as the average measurements of tibiofemoral motion, further in vivo analysis and long-term studies on the femoral internal rotation and high contact pressure on the lateral side are still required.