ABSTRACT
A three-dimensional finite element model of a total cementless carpometacarpal prosthesis coated with hydroxyapatite was developed in order to study the coating and the bone/implant interface in two clinical situations for key pinch. A semi-automatic mesh generator was developed. Finite element analysis was carried out using the commercial ABAQUS® package. Hydroxyapatite mechanical characteristics were determined, in order to take into account this biomaterial behaviour in the finite element model. The hydroxyapatite/trabecular bone interface was either perfectly bonded representing a long term situation where the implant is perfectly osteointegrated, or considered in contact with friction at bone/implant interface in the early post-operative situation. The finite element model predicted, immediately after surgery (non linear interface) and in the long term after bony ingrowth (fully bonded interface), large stresses in the hydroxyapatite coating.
