Titanium foams replace injured bones

Resembling the inside of a bone in terms of its structural configuration, the researchers claim that as well as being less rigid than conventional implants, the foam also promotes ingrowth into surrounding bones. A new kind of implant made of titanium foam could soon replace injured bones. Not only does it resemble the inside of a bone in terms of its structural configuration – it promotes ingrowth into surrounding bones. The TiFoam project, is a result of research partners who have aimed to demonstrate the viability of titanium foam for replacement of defective vertebral bodies. Materials scientists from the Fraunhofer institutes IFAM and IKTS – the Institute for Ceramic Technologies and Systems in Dresden – physicians from the medical centre at the Technical University of Dresden and from several companies were involved in developing titanium foam. Project partner InnoTERE already announced that it would soon develop and manufacture TiFoam-based bone implants. The titanium foam is the result of a powder metallurgy based molding process that already exists in the industrial production of ceramic filters for aluminum casting. Open cell polyurethane (pu) foams are saturated with a solution consisting of a binding medium and a fine titanium powder. The powder cleaves to the cellular structures of the foams and the pu and binding agents are then vapourised. What remains is a semblance of the foam structures, which is ultimately sintered. This applies foremost to the balance between extreme durability and minimal rigidity. The former is an important precondition for its use on bones, which have to sustain the forces of both weight and motion. Bone like rigidity allows for stress forces to be transmitted; with the new formation of bone cells, it also fosters healing of the implant. Consequently, stress can and should be applied to the implant immediately after insertion.