  In the framework of the recently developed asymptotic models for
tibio-femoral contact incorporating frictionless elliptical contact interaction
between thin elastic, viscoelastic, or biphasic cartilage layers, we apply an
asymptotic modeling approach for analytical evaluating the sensitivity of
crucial parameters in joint contact mechanics due to small variations in the
thicknesses of the contacting cartilage layers. The four term asymptotic
expansion for the normal displacement at the contact surface is explicitly
derived, which recovers the corresponding solution obtained previously for the
2D case in the compressible case. It was found that to minimize the influence
of the cartilage thickness non-uniformity on the force-displacement
relationship, the effective thicknesses of articular layers should be
determined from a special optimization criterion.
