Zusammenfassung
Fragestellung: Ist die Pressfit-Verankerung von zementfreien Hüftpfannen abhängig von der Rauigkeit des Poles? Um diese Frage zu beantworten, wurde der primäre Pressfit zweier zementfreier Hüftpfannen, die sich nur hinsichtlich der Rauigkeit des Poles unterscheiden, mittels einer finiten-Elemente-Analyse (FEA) verglichen.
Material und Methode: Die Werkstoffeigenschaften des Knochens wurden als homogen, isotrop und linear-elastisch angenommen. Es wurden die Materialkennwerte von spongiösem Knochen bei drei unterschiedlichen Knochendichtewerten verwendet. Die getroffene Annahme der Isotropie stellt eine Näherung dar.
Ergebnisse: Der Vergleich der beiden Prothesenformen zeigte, dass beide Modelle ähnliche Verformungen und Spannungen im Knochen verursachen.
Schlussfolgerungen: Daher kann festgestellt werden, dass die Prothese mit abgefräster Oberfläche der mit ungefräster Oberfläche hinsichtlich der Pressfit-Verankerung in der finiten-Elemente-Analyse mechanisch gleichwertig ist.
Abstract
Aim: Does the pressfit anchorage of cementless acetabular cups depend on the roughness of the pole? To answer this question the primary pressfit of two cementless acetabular cups which differ only with regard to the roughness of their poles were compared by means of finite elements analysis.
Materials and methods: It was assumed that the material properties of bone are homogeneous, isotropic and linearly elastic. Material-specific values of cancellous bone with three different bone densities were used. Assumption of isotropy represents an approximation.
Results: Comparison of the two prosthesis designs revealed that both designs/shapes cause similar patterns of bone deformation and tension.
Conclusions: It can therefore be concluded that with regard to pressfit anchorage the prosthesis with milled polar surface is according to FEA mechanically equivalent to the prosthesis with non-milled polar surface.
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