Ramadier J O, Lelong P, Dupont J Y
Rev Chir Orthop Reparatrice Appar Mot. 1980 Nov-Dec;66(8):507-14.
The authors have operated on 15 hips using a total prosthesis comprising a metallic head and plastic cup cemented in the acetabulum. The acetabular component is thicker at its upper part to accommodate eventual wear in the plastic. In all cases the cup rotated through 180 degrees so that, after several months, the thicker part was situated at the lower pole of the acetabulum. In two cases, a fracture of the cup was found. The cause of this abnormal rotation can be explained by a torque action taking place at each step because of the eccentric design of the cup. This was demonstrated by a prosthesis inserted into a cadaver and tested by simulated walking. 45 kilometres of walking were sufficient to provoke a rotation of 90 degrees. Conclusions are given on the use of such eccentric cups which should be avoided.
作者使用一种全髋关节假体对15例患者进行了手术，该假体包括一个金属股骨头和一个用骨水泥固定在髋臼中的塑料杯。髋臼部件的上部较厚，以适应塑料部件最终的磨损。在所有病例中，塑料杯均旋转了180度，因此几个月后，较厚的部分位于髋臼的下极。在两例病例中，发现了塑料杯骨折。这种异常旋转的原因可以解释为，由于髋臼杯的偏心设计，在每一步都会产生扭矩作用。将一个假体插入尸体并通过模拟行走进行测试，证明了这一点。行走45公里足以引起90度的旋转。文中给出了关于此类偏心髋臼杯使用的结论，应避免使用。
