We prove the conical differentiability of the solution to a boneremodeling contact rod model, for given data (applied loads andrigid obstacle), with respect to small perturbations of the crosssection of the rod. The proof is based on the special structure ofthe model, composed of a variational inequality coupled with anordinary differential equation with respect to time. Thisstructure enables the verification of the two followingfundamental results: the polyhedricity of a modified displacementconstraint set defined by the obstacle and the differentiabilityof the two forms associated to the variational inequality.
