Bone Replacement Studies Using Titanium Chamber Models in Small Animals

Summary

When Kiel bone was introduced clinically, animal experiments seemed to demonstrate its efficiency. It later became obvious that the utilized experimental models were insufficiently sensitive. This presentation discusses the demands on a model for evaluating materials with claimed “osteoinductive” properties, and describes some attempts to meet these demands by using titanium bone chamber techniques. A new type of chamber allows studies of the osteoconductive performance of cancellous bone grafts in rats. This model makes it possible to carry out large series of experiments. It was shown that defatting increased bone graft incorporation, and that defatted bone grafts performed even better if they were pretreated with basic Fibroblast Growth Factor (bFGF). Ethylene oxide sterilization had a dramatic negative effect even though residuals were below levels recommended by the FDA. Radiation had no effect. As fibrous tissue ingrowth into porous materials was usually affected in the same way as bone ingrowth, it appears that the term “osteoconduction” has to be further defined.