[Material and technical aspects of mega prostheses]

So-called mega implants were developed especially for the therapy of tumour diseases, but since these prostheses are considered to be custom-made products, they are excluded from the usual test specifications required by the German Act on Medical Devices. Based on the fact that these mega prostheses are specially manufactured and meant to be implanted in a certain patient, only casting technologies can be used. Forging procedures commonly used for so-called normal prostheses cannot be applied here. Thus only Co-Cr-Mo cast alloys can be used. Additional technologies are used for manufacturing partial pelvic implants. By means of CT plastic models are made so that the corresponding mega implants can be properly customized afterwards. Nowadays numerous bloomed surfaces and surface structures are offered to improve the engraftment behaviour.