Furman Bridgette D, Lipman Joseph, Kligman Mordechai, Wright Timothy M, Haas Steven B
Department of Biomechanics, Hospital for Special Surgery, New York, NY 10021, USA.
Clin Orthop Relat Res. 2008 Nov;466(11):2650-5. doi: 10.1007/s11999-008-0422-1. Epub 2008 Aug 14.
Polyethylene tibial post wear in posterior-stabilized knee designs is a major problem. The Insall-Burstein II (IB PS II) reportedly has severe anterior wear of the post in retrieved implants. We hypothesized the more anterior placement in the IB PS II would be reflected in greater wear at the anterior face than the IB PS I. We examined 234 retrieved inserts using subjective scales to grade post damage and wear. Of the IB PS II inserts, 38% demonstrated severe wear compared with only 25% of IB PS I inserts. The most prevalent damage location for the IB PS II was the anterior face, whereas the IB PS I sustained wear mainly on the medial face. While the IB PS post was not designed to constrain posterior femoral displacement, our observations confirm contact in hyperextension or other paradoxic anterior tibial translation is common and design-dependent. Minimizing wear and damage through proper post placement and changes in implant design to anticipate contact on the anterior post should be considered for future posterior stabilized knee replacements. These changes cannot occur in isolation, however, because changes in post placement and design also depend on their relation to the shape and location of the tibial bearing surfaces.
在后稳定型膝关节设计中，聚乙烯胫骨柱磨损是一个主要问题。据报道，Insall-Burstein II（IB PS II）在取出的植入物中存在严重的柱体前部磨损。我们推测，IB PS II中柱体更靠前的位置会导致其前表面比IB PS I有更大程度的磨损。我们使用主观量表对234个取出的衬垫进行检查，以对柱体损伤和磨损进行分级。在IB PS II衬垫中，38%表现出严重磨损，而IB PS I衬垫中只有25%如此。IB PS II最常见的损伤部位是前表面，而IB PS I的磨损主要发生在内侧表面。虽然IB PS柱体并非设计用于限制股骨后移，但我们的观察结果证实，在膝关节过伸或其他反常的胫骨前向平移时的接触很常见，且与设计有关。对于未来的后稳定型膝关节置换术，应考虑通过适当的柱体放置和改变植入物设计来尽量减少磨损和损伤，以预测前柱体上的接触。然而，这些改变不能孤立发生，因为柱体放置和设计的改变还取决于它们与胫骨承载面形状和位置的关系。
