FE-Simulation in der klinischen Osteoporoseforschung^[*]

Zusammenfassung

Altersbedingte Osteoporose erhöht des Frakturrisiko. Übliche Diagnoseverfahren basieren auf DXA. Leider sind diese ungenau und erklären oft nicht die Effekte von Behandlungen. Eine neue Methode zur Bestimmung der Knochenfestigkeit beginnt derzeit, sich zu etablieren – die Finite-Elemente-Methode (FEM). Diese universelle, im Bereich der Technik weit verbreitete, Methode erlaubt es, die Diagnose und den Behandlungserfolg besser vorauszusagen als DXA. CT-basierende FEModelle sind stark von der Bildauflösung abhängig. In diesem Überblicksartikel werden drei unterschiedliche Modelltypen (μCT, HRpQCT, QCT) vorgestellt und die Ergebnisse von densitometrischen und FE-Analysen verglichen. Dabei waren die FE-Ergebnisse den densitometrischen immer überlegen. Darüber hinaus erlaubt die FEM die Angabe eines biomechanischen Frakturrisikos. Dieser Vorteil der FE-Methode muss jedoch im Licht der höheren Röntgendosen und Betriebskosten der CT-Bildgebung betrachtet werden. Zukünftig wird die FE-Methode klinisch eine weite Verbreitung finden – die Frage ist nur wann und wie!

Summary

Osteoporosis leads to higher bone fracture risk and is diagnosed by DXA. Unfortunately, DXA is not a perfect surrogate of bone strength and can often not explain the effect of pharmacological treatment. Currently a new methodology to determine bone strength becomes established: the Finite element method (FEM). This universal, widely accepted engineering method allows to diagnose bone fragility and the effect of treatment better than DXA and QCT. The CT-based FE models depend highly on image resolution. In this review, three types of models are presented (μCT, HR-pQCT, QCT) and the results of densitometric and FEM results are compared. In these cases, the FE results were always superior to densitometric ones. In addition, FE allows to determine a biomechanical fracture risk. Nevertheless, this advantage of FEM needs to be considered in the light of higher x-ray dose and service costs associated with CT imaging. In the future, FEM will be widely applied in the clinics, the question is only when and how!

Keywords

Osteoporosis - Finite element method - bone strength

Schlüsselwörter

Osteoporose - Finite-Elemente-Methode - Knochenfestigkeit

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