BONE FIXATION OF CERAMIC-COATED AND FIBER TITANIUM IMPLANTS - A STUDY IN WEIGHT-BEARING RATS

We compared the fixation of glass ceramic-coated titanium and fiber titanium implants using a simple weight-bearing model in rats. The chemical composition of the glass ceramic was similar to 45S5F Bioglass. One hundred and eight male Wistar rats were operated on. A segment of their right tibias was replaced by a disc-shaped implant with a central hole. A stable osteosynthesis was completed by means of an intramedullary nail and a tension band. Thirty-six rats received glass ceramic-coated and 36 fiber titanium implants. In 36 rats osteotomies were performed. All animals survived without complications until scheduled sacrifice at 3, 12 and 26 weeks, postoperatively. The ultimate bending moments of the fiber titanium-bone interfaces and the osteotomies increased with time, and approached the levels of the contralateral, intact tibias at the 12th and 26th week. Also, the ultimate bending stresses increased from the 3rd to 12th week. After 26 weeks the fiber titanium-bone interfaces had reached about 45 per cent, and the osteotomies about 75 per cent of the strength of the intact tibias. All the glass ceramic-coated implants were loose, and at 26 weeks there was no coating left.