If joint-preserving measures are no longer possible the orhtopedic hospital offers a complete spectrum of prosthetic knee-joint replacement. If the disease is limited a monocondylar prosthesis type Miller-Galante® (Zimmer), figure 1 is used. The components of this prosthesis are anchored to the bone with cement. They are designed in a way that few bone has to be resected for the implantation. The Miller Galante® system is one of the few systems worldwide with documented good 10 year-survival results. Most knee-arthroses are treated by the modular bicondylar knee-prostheses system type INTERAX® (Stryker Howmedica) figure 2. Adapted to the particular situation the individually best suiting prosthesis according to function and size of the INTERAX® assortement is selected. For the INTERAX® system there exists a model with fixed polyethylen-plateau, as well as a system with a so called mobile plateau. In considerable deformities a posterior-stabilized version is used, which guarantees good stability and range of motion, even if the posterior cruciate ligament had to be sacrificed. As all systems are compatible among each other the surgeon has intraoperatively free choice to select the best fitting implant for the individual situation. Worst deformities in elderly patients require - in rare cases - the use of a total, self stabilizing knee-prosthesis, which is not dependent on the joint capsule or the ligaments of the patient. In these cases we use the system GSB® (Centerpulse).
For revision surgery in loosened knee-prostheses INTERAX offers a revision option: longer prosthesis stems, additional metal components for reinforcement of the standard components and special adjustment and implantation systems allow the control of bone defects (figure 3). The attachment of the knee prosthesis to the bone is done exclusively by cement, as this is - according to the actual knowledge - the prerequisite for an unobjectionable, unproblematic implantation. In knee arthroplasty cementless systems are - in contrary to hip arthroplasty - not of a proven advantage, but may bear the risk of lacking integration into the bone and of early loosening.
Figure 4 shows a knee after implantation of a knee prosthesis (Interax® standard knee prosthesis).
Figure 1 Monocondylar knee prosthesis system type Miller Gallante® (Zimmer)
Figure 2 INTERAX® standard knee prosthesis with replacement of all joint surfaces but preservation of the posterior cruciate ligament, collateral ligaments and joint capsule
Figure 3 INTERAX® revision system for control of bone defects after implant exchange (x-ray result).
Figure 4 X-ray ap and lateral after prosthetic replacement with an Interax® standard-knee
