LINK has decades of experience in the use of UHMWPE, and this was particularly valuable in the design of the cemented acetabular cups. The high quality of the polyethylene demonstrably minimizes abrasion suffered by the components, and thereby reduces the risk of osteolysis. Consequently, the incidence of component loosening is very low. In addition to the Standard UHMWPE, we also supply the system in acetabular cups made of X-LINKed UHMWPE. This highly crosslinked polyethylene makes it possible to achieve even lower abrasion levels.2, 7, 8
In addition to the material properties, the external shape of the acetabular cups help to prevent loosening. Radial notches in the surface create a high degree of cement contact and allow air to escape when the implant is pressed into the cement bed.4 Approximately 0.5 mm of play between prosthesis head and acetabular cup allows for “lubrication” by body fluids.10 Furthermore, spacers on the rear surface of the acetabular cup permit a uniform cement coating. This surface design increases the stability of the cup in the acetabulum, thereby largely eliminating the risk of loosening.5 This design is used successfully in the FC, FAL, and IP Polyethylene Acetabular Cups and also in the Lubinus Acetabular Cup.
Another feature of the cemented polyethylene acetabular cups is the high cup rim, which projects beyond the spherical shape. The Endo-Model Acetabular Cup features an integral medioventral recess, which provides a wide range of motion and protects the femoral nerve and psoas tendon, which can be irritated by the cup rim in the case of larger diameters.4 In addition, it has a partial peripheral rim, unlike the IP Acetabular Cup and the Lubinus Acetabular Cup. This rim increases the cement compression, which in turn makes for better stabilization of the cup in the cement coating.9 In combination with the LINK SPII Lubinus Femoral Stem, this system offers an outstanding, anatomically adapted, cemented hip prosthesis.