The pattern of healing following implantation of heterogenous anorganic compact bone in sheep

Abstract

Bovine cortical ethylenediamine extracted (anorganic) bone was implanted into surgically created defects in the long bones and tubera coxae of sheep. In some defects the anorganic bone was implanted as a block, in others the material was fragmented and passed through a 15 mesh/in, sieve, and control defects were allowed to fill with blood. The sites of the defects were studied histologically after periods ranging from 14 to 392 days. The blocks of anorganic cortical bone were revascularized, and new bone formed both on the outer surfaces and within the vascular canals. Thereafter, the material showed little change, and even after more than a year the greater part of the implant remained. Fragmented anorganic bone became more intimately incorporated in the new host bone, but the fragments were still present over a year after implantation. There was no evidence of foreign body reaction, or of osteoclastic resorption; the anorganic bone appeared to act as an inert foreign body. When implanted into a naturally osteogenic site, as in these experiments, the material tended to impede healing. However, there was evidence that either form of implant prevented the herniation of the bone marrow which appeared to be the cause of imperfect healing in some control defects.