[Morphological results after an experimental transplantation of autogenous cancellous bone in dogs (author's transl)].

Cell activity during the period of healing of an autogenous cancellous graft inserted into an artificial continuity defect of the ulna was studied in 20 adult dogs by light microscopy using the semithin sectioning technique. The defects were stabilised by osteosynthesis using metal plates and screws. The animals were divided into 4 groups and the autografts were investigated 1, 2, 4 and 8 weeks after transplantation. Histologic analysis showed, that ... 1. one week after transplantation, undifferentiated cells resembling reticular cells, haemocytoblasts and many closely packed osteoblasts were scattered among the trabecular network of the autogenous cancellous graft. The survival of transplanted cells in our opinion is evident, by the absence of any sign of cell death or macrophage activity. 2. two to 4 weeks after transplantation a remarkable increase of the osteoblast activity was noted. This osteogenic cell activity was mainly directed toward bone formation along the surface of contact of the autograft with the adjoining bone and there was more than one layer of osteoblasts and osteoid. Osteoblasts were also found lying along the trabecular surface of transplanted cancellous bone, but here they were arranged in a layer, which was usually only one cell deep. 3. eight weeks after transplantation there was a remarkable change in the appearance of the autogenous cancellous graft. The activity of the multinucleated osteoclasts was significantly increased in the direction of the surface of contact of the autograft with the compact receptor bone. Evidently the osteoclasts produce the prior conditions for a closer contact of the autogenous cancellous graft with the adjoining compact bone.