Three-dimensional methods for quantification of cancellous bone architecture

Critical evaluation of known bone material properties to realize anisotropic FE-simulation of the proximal femur.

Influence of muscle forces on femoral strain distribution

We have reviewed highlights of the research in trabecular bone biomechanics performed over the past 20 years. Results from numerous studies have shown that trabecular bone is an extremely heterogeneous material--modulus can vary 100-fold even within the same metaphysis--with varying degrees of anisotropy. Strictly speaking, descriptions of the mechanical properties of trabecular bone should therefore be accompanied by specification of factors such as anatomic site, loading direction, and age. Research efforts have also been focused on the measurement of mechanical properties for individual trabeculae, improvement of methods for mechanical testing at the continuum level, quantification of the three-dimensional architecture of trabecular bone, and formulation of equations to relate the microstructural and continuum-level mechanical properties. As analysis techniques become more sophisticated, there is now evidence that factors such as anisotropy and heterogeneity of individual trabeculae might also have a significant effect on the continuum-level properties, suggesting new directions for future research. Other areas requiring further research are the time-dependent and multiaxial failure properties at the continuum level, and the stiffness and failure properties at the lamellar level. Continued research in these areas should enhance our understanding of issues such as age-related bone fracture, prosthesis loosening, and bone remodeling.

A 20-year perspective on the mechanical properties of trabecular bone.

The effect of specimen geometry on the mechanical behaviour of trabecular bone specimens.

Schlüsselwörter: Gebietsfestlegung im Knochenschnitt, Definition der Orthotropierichtungen, Elastizitäts-, Schubmoduli, Querkontraktionszahlen, Dehnungskoeffizientenmatrizen, Altersabhängigkeit der Materialkennwerte. Für sechs typische Strukturgebiete der Spongiosa im Schenkelkopf des proximalen Femur-Teils wurde unter Anwendung statistischer Auswertungsmethoden auf die experimentell gewonnenen Resultate und unter Annahme topographisch orthotropen Festigkeitsverhaltens des Knochenwerkstoffes die entsprechenden Dehnungskoeffizientenmatrizen [S] berechnet. In der Auswertung werden Zusammenhänge zwischen Strukturdichte und Strukturaufbau der Spongiosa aufgezeigt, sowie die Abhängigkeits des Elastizitätsmoduls, des Schubmoduls und der Querkontraktionszahl von der Strukturdichte, vom Strukturaufbau des Knochenmaterials, vom Geschlecht und vom Lebensalter des Menschen auf der Basis statistischer Methoden.

P Knauss

Papers

[Material properties and strength behaviour of spongy bone tissue at the coxal human femur. (author's transl)].