An investigation of the contribution of the extraosseous tissues to the diaphyseal fracture callus using a rabbit tibial fracture model and in situ immunocytochemical localisation of osteocalcin.

The extraosseous tissue contribution to diaphyseal fracture callus has been investigated using a rabbit tibial fracture model and osteocalcin immunocytochemistry. The extraosseous tissues were isolated for study by reaming and nailing an osteotomy and excising 2 cm of periosteum on either side of the osteotomy. Specimens obtained from the healing fractures at 1 and 2 weeks after operation, respectively, were decalcified and stained for osteocalcin, a bone-specific protein, using an indirect immunoperoxidase method. The positively stained osteogenic cells appeared to be derived exclusively from the remnant of the periosteum.