Moonot Pradeep, Shang Mu, Railton Gilbert T, Field Richard E, Banks Scott A
South West London Elective Orthopaedic Centre, Dorking Road, Epsom, Surrey, UK.
Knee. 2010 Jan;17(1):33-7. doi: 10.1016/j.knee.2009.06.009. Epub 2009 Jul 23.
Knee arthroplasties are designed to accommodate flexion, axial rotation and anteroposterior (AP) translation. Axial rotation during extension varies, with some rotating platform devices allowing unrestricted rotation while some conforming fixed-bearing designs almost none. The purpose of this study was to examine in vivo kinematics of a fixed-bearing medial rotation-type arthroplasty (MRK) during weight-bearing activities. Fifteen knees with a medial pivot TKA design were studied during step and pivot activities using lateral fluoroscopy and model-image registration. Average knee kinematics during the step activity showed little AP translation or rotation from 0 degrees -100 degrees flexion. During the pivot activity, the mean tibial internal rotation in individual knees was 7 degrees (3 degrees -19 degrees ). Mean condylar translations for individual knees were 3mm medially and 5mm laterally. The medial pivot prosthesis design provides anteroposterior stability during demanding activities, and exhibits a medial pivot motion pattern when subjected to twisting.
膝关节置换术旨在适应膝关节的屈曲、轴向旋转和前后（AP）平移。伸展过程中的轴向旋转情况各不相同，一些旋转平台装置允许无限制旋转，而一些顺应性固定承重设计几乎不允许旋转。本研究的目的是研究固定承重内侧旋转型关节成形术（MRK）在负重活动期间的体内运动学。使用外侧荧光透视和模型图像配准技术，对15例采用内侧枢轴全膝关节置换（TKA）设计的膝关节在迈步和枢转活动期间进行了研究。迈步活动期间的平均膝关节运动学显示，从0度至100度屈曲时，几乎没有前后平移或旋转。在枢转活动期间，各个膝关节的平均胫骨内旋角度为7度（3度至19度）。各个膝关节的平均髁突平移距离为内侧3mm，外侧5mm。内侧枢轴假体设计在高要求活动期间提供前后稳定性，并且在受到扭转时呈现内侧枢转运动模式。
