Werner F, Foster D, Murray D G
J Bone Joint Surg Am. 1978 Apr;60(3):342-8.
Knee prostheses of eight different designs were tested experimentally to determine the axial torque necessary to rotate the tibial component relative to the femoral component with the prosthesis positioned at or near full extension. The results represent transmitted torque as a function of axial rotation. For six designs, the transmitted torque was 11.3 newton-meters (100 inch-pounds) or greater at 6 degrees of rotation, with an axial load of 1556.8 newtons (350 pounds). These prostheses either had close conformation between femoral and tibial components, or were mechanically linked. In these prostheses, the geometry of the articulating surfaces was the primary determinant of torque. For the other two types, under similar loading conditions the transmitted torques were 2.5 newton-meters (twenty-two inch-pounds) at 6 degrees of rotation. These prostheses were designed to allow greater freedom for rotation, and hence for them the primary determinant of torque was friction between the articulating surfaces. The predictive value of this torque characteristic relative to the incidence of loosening will have to be determined by comparison with clinical experience.
对八种不同设计的膝关节假体进行了实验测试，以确定当假体处于或接近完全伸展位置时，使胫骨部件相对于股骨部件旋转所需的轴向扭矩。结果表示传递扭矩作为轴向旋转的函数。对于六种设计，在6度旋转时，轴向载荷为1556.8牛顿（350磅），传递扭矩为11.3牛顿米（100英寸磅）或更大。这些假体的股骨和胫骨部件之间贴合紧密，或者是机械连接的。在这些假体中，关节表面的几何形状是扭矩的主要决定因素。对于另外两种类型，在类似的加载条件下，6度旋转时的传递扭矩为2.5牛顿米（22英寸磅）。这些假体设计为允许更大的旋转自由度，因此对于它们来说，扭矩的主要决定因素是关节表面之间的摩擦力。这种扭矩特性相对于松动发生率的预测价值必须通过与临床经验进行比较来确定。
