On foundations of discrete element analysis of contact in diarthrodial joints.

Information about the stress distribution on contact surfaces of adjacent bones is indispensable for analysis of arthritis, bone fracture and remodeling. Numerical solution of the contact problem based on the classical approaches of solid mechanics is sophisticated and time-consuming. However, the solution can be essentially simplified on the following physical grounds. The bone contact surfaces are covered with a layer of articular cartilage, which is a soft tissue as compared to the hard bone. The latter allows ignoring the bone compliance in analysis of the contact problem, i.e. rigid bones are considered to interact through a compliant cartilage. Moreover, cartilage shear stresses and strains can be ignored because of the negligible friction between contacting cartilage layers. Thus, the cartilage can be approximated by a set of unilateral compressive springs normal to the bone surface. The forces in the springs can be computed from the equilibrium equations iteratively accounting for the changing contact area. This is the essence of the discrete element analysis (DEA). Despite the success in applications of DEA to various bone contact problems, its classical formulation required experimental validation because the springs approximating the cartilage were assumed linear while the real articular cartilage exhibited non-linear mechanical response in reported tests. Recent experimental results of Ateshian and his co-workers allow for revisiting the classical DEA formulation and establishing the limits of its applicability. In the present work, it is shown that the linear spring model is remarkably valid within a wide range of large deformations of the cartilage. It is also shown how to extend the classical DEA to the case of strong nonlinearity if necessary.

[1]  H. Yoshida,et al.  Prediction of femoral head collapse in osteonecrosis. , 2006, Journal of biomechanical engineering.

[2]  Shen-Haw Ju,et al.  Efficient finite element method for contact analysis of articular joints , 1996 .

[3]  W M Lai,et al.  An asymptotic solution for the contact of two biphasic cartilage layers. , 1994, Journal of biomechanics.

[4]  H. Grootenboer,et al.  Articular contact in a three-dimensional model of the knee. , 1991, Journal of Biomechanics.

[5]  R. E. Rowlands,et al.  Analysis of frictional joint contact , 1993 .

[6]  V C Mow,et al.  Finite deformation biphasic material properties of bovine articular cartilage from confined compression experiments. , 1997, Journal of biomechanics.

[7]  S. Cowin Bone poroelasticity. , 1999, Journal of biomechanics.

[8]  V. Mow,et al.  Biphasic creep and stress relaxation of articular cartilage in compression? Theory and experiments. , 1980, Journal of biomechanical engineering.

[9]  E. Chao,et al.  Normal hip joint contact pressure distribution in single-leg standing--effect of gender and anatomic parameters. , 2001, Journal of biomechanics.

[10]  V C Mow,et al.  Contact analysis of biphasic transversely isotropic cartilage layers and correlations with tissue failure. , 1999, Journal of biomechanics.

[11]  Walter Herzog,et al.  An articular cartilage contact model based on real surface geometry. , 2005, Journal of biomechanics.

[12]  Anna Stankiewicz,et al.  Anisotropy, inhomogeneity, and tension-compression nonlinearity of human glenohumeral cartilage in finite deformation. , 2005, Journal of biomechanics.

[13]  W Herzog,et al.  Evaluation of the finite element software ABAQUS for biomechanical modelling of biphasic tissues. , 1997, Journal of biomechanics.

[14]  Tadahiko Kawai,et al.  研究速報 : A New Element in Discrete Analysis of Plane Strain Problems , 1977 .

[15]  E. Chao,et al.  Three-dimensional dynamic hip contact area and pressure distribution during activities of daily living. , 2006, Journal of biomechanics.

[16]  G A Ateshian,et al.  A theoretical solution for the frictionless rolling contact of cylindrical biphasic articular cartilage layers. , 1995, Journal of biomechanics.