The function of the donor tissue in experimental operations with radioactive bone grafts.

Abstract

The experiments show, with the aid of radioisotope labeled rabbit bone transplants into clean hosts, that the donor tissue can accomplish its purpose (to induce the host to fill a defect, to fuse a joint, to unite a fracture) when less than one-third of its total mass has been absorbed and replaced by the host. The bone matrix and the bone mineral are absorbed together and the labeled mineral constituents are dissolved and carried into the systemic circulation of the host and not transferred locally to the host bed. When a bone graft takes,'' the donor tissue becomes adjoined to the host by a cement line formed by the host by condensation of mucopolysaccharides with the histochemical characteristics of chondroitin sulfate. When a bone graft operation fails, the donor tissue becomes encapsulated in an envelope of fibrous tissue and is virtually outside the body. In a successful bone graft the host grows into the donor tissue in an orderly pattern and not by haphazard growth; the trabeculae of new bone from the host bed grow into the donor and each one finds a trabocula of deal bone on which to attach itself in the most efficient way; thus the functionmore » of the donor tissue in all bone graft operations is to provide a network of slowly absorbed surfaces upon which the host is induced to condense the cement line and deposit the new bone. The induction of new bone formation by a bone transfer is a non-specific reaction, the mechanism of which is not yet known, and requires further investigation.« less