Department of Orthopaedic Surgery, Hannover Medical School, Anna-von-Borries-Strasse 1-7, Hannover, Germany,
Knee Surg Sports Traumatol Arthrosc. 2013 Oct;21(10):2392-7. doi: 10.1007/s00167-012-1986-6. Epub 2012 Apr 4.
Lack of the anterior cruciate ligament in total knee arthroplasty results in paradoxical movement of the femur as opposed to the tibia under deep flexion. Total knee arthroplasty with mobile-bearing inlays has been developed to provide increased physiological movement of the knee joint and to reduce polyethylene abrasion. The aim of this study was to perform an in vitro analysis of the kinematic movement in the sagittal plane in order to show differences between fixed- and mobile-bearing TKA in comparison with the natural knee joint.
Seven knee joints of human cadaver material were used in a laboratory experiment. Fixed- and mobile-bearing inlays were tested in sequences under isokinetic extension in so-called kinemator for knee joints, which can simulate muscular traction power by the use of hydraulic cylinders, which crossover the knee joint. As a target parameter, the a.p. translation of the tibio-femoral relative movement was measured in the sagittal plane under ultrasound (Zebris) control.
The results show a reduced tibial a.p. translation in relation to the femur in the bearing group compared to the natural joint. In the Z-axis, between 110° and 50° of flexion, linear movement decreases towards caudal movement under extension. Admittedly, the study did not show differences in the movement pattern between "mobile-bearing" and "fixed-bearing" prostheses.
Results of this study cannot prove functional advantages of mobile-bearing prostheses for the knee joint kinematic after TKA. Both types of prostheses show typical kinematics of an anterior instability, hence they were incapable of performing physiological movement.
全膝关节置换术中前交叉韧带缺失会导致股骨在深度弯曲时下相对于胫骨出现反常运动。为了提供膝关节更生理性的运动并减少聚乙烯磨损，已开发出带活动衬垫的全膝关节置换术。本研究的目的是对矢状面的运动学进行体外分析，以显示固定和活动衬垫 TKA 与自然膝关节之间的差异。
在实验室实验中使用了 7 个人体尸体膝关节。在所谓的膝关节运动模拟器中，依次测试了固定和活动衬垫，该模拟器可以通过使用液压缸模拟肌肉牵引力，从而使膝关节交叉。作为目标参数，在超声（Zebris）控制下测量矢状面中胫骨-股骨相对运动的前后平移。
结果表明，与自然关节相比，在轴承组中，相对于股骨，胫骨的前后平移减小。在 Z 轴上，在 110°到 50°的弯曲之间，在伸展时线性运动向尾侧运动减少。诚然，该研究并未显示“活动衬垫”和“固定衬垫”假体之间的运动模式差异。
本研究的结果不能证明活动衬垫假体在 TKA 后对膝关节运动学有功能优势。两种类型的假体都显示出前不稳定的典型运动学，因此它们无法进行生理性运动。
