| 摘要 |
Artificial bone, especially for use in a hip joint prosthesis, comprises an inert ceramic body. This is preferably porous, the pores being continuous and communicating and the pores are preferably filled with a synthetic resin to give increased flexural strength to the structure. A suitable ceramic material is made from alumina, silica and magnesium and/or calcium carbonates. This is shaped and pre-fired at between 1600 DEG and p 2000 DEG F. to decompose the carbonates and give a porous, open cell structure. It is relatively soft and may be readily worked by ordinary tools to the desired dimensions, after which it is finally fired at between 2300 DEG and 2700 DEG F. Introduction of the synthetic resin, which is preferably an epoxy or polyurethane resin, is carried out in a closed chamber by initial evacuation followed by impregnation with the resin under pressure. To assist fixation of the prosthesis by bone or tissue growth it is preferred to have the superficial pores of the shank free from resin and this may be achieved by dipping it in a solvent, such as methylene dichloride, or by initially filling them with wax which is subsequently removed. Two forms of hip prosthesis are described, one of which is made solid from porous, ceramic material while the other has a tapering hole throughout the length of its shank so that the finished product has a core of synthetic resin. |
