[Biocorundum--a new/type of poreless ceramic material of aluminum oxide for the manufacture of the elements of hip joint prosthesis. Biological and technological studies].

The Institute of Refractories Materials in Gliwice undertook researches in the field of technology of a new ceramic material of aluminium oxide for production of coxal joint endoprostheses. A poreless ceramic material of high chemical purity and density and required microstructure and good resistance to fracture, was achieved. The new ceramic material was called Biocorundum. By means of a similar technology also series of samples were produced for testing the biocompatibility of the material. Biological studies were carried out in the Department of Experimental Surgery and Biomaterials Research, Chair of Traumatologic Surgery, Medical Academy of Wroclaw. The studies comprised: 1. laboratory and toxicological tests in vitro of water extracts, 2. pathomorphological studies after intramuscular, peritoneal and intra-bone implantation of samples of the material in rats and piglets, 3. ultrastructural scanning studies of the implantation in rats and pigs and after 3- and 6-months long keeping in the Ringer solution. Preliminary studies and biological studies in vitro have shown a complete conformity of the material with the requirements. Tissue reactivity was studied on 36 Wistar rats. By pathomorphological studies a systematic macroscopic and microscopic estimation was possible. They have shown only minimal tissue reactivity to biocorundum implantation. In experimental studies on 14 piglets the biocorundum grafts were implanted into the tibia epiphysis for 3- and 6-months. Clinical, pathomorphological and X-ray studies were carried out. In all cases the Biocorundum grafts healed without any complications. On the basis of pathomorphological studies, the tissue reactivity around the grafts were estimated as minimal. This shows a high biocompatibility of the ceramic material. In X-ray studies were observed around the grafts small osteosclerotic changes and periosteum stratification. These changes resulted after surgical interventions in quickly growing piglets. Complementary studies of the surface of the material by scanning microscopy after 3 months long implantation and after 3 months long contact with the Ringer solution did not show any changes in comparison with the surface of the initial samples. After 6 months long implantation in individual samples rounding of the ceramic material grain edges were found, which could result from biological corrosive power. This agree with the findings of other studies on other ceramic aluminium oxide materials. The achieved results of complex studies of biocompatibility of the new poreless material developed in Poland--Biocorundum--have shown its complete biological suitability for production of elements of osteoarticul