A STUDY OF BONE REMODELING USING METAL-POLYMER LAMINATES

Bone remodeling due to stress-shielding has been studied using a model system consisting of metal-polymer laminated fixation plates securely fixed to canine femurs. The plate stiffness was controlled by varying the ratio of metal facing to polymer core thickness in the laminate design while secure fixation to bone was achieved by providing a porous bone interfacing surface for the ingrowth of bone from the periosteal surface. Observations of laterally and medially placed plates indicated resorption in the area of the periosteal and endosteal bone surfaces respectively, for the higher stiffness composite plates used. The results indicate that plate stiffness greater than approximately 70 GPa (axial) and 6 N m**2 (flexural) will result in extensive bone remodeling in the canine femur after a six-month implantation period. Facing materials were 316L stainless steel or Ti-6AL-4V, with polycarbonate or polypropylene cores.