[Radiographic and histologic observations of autoclaved and non autoclaved allografts in the distal femoral metaphysis in dogs].

PURPOSE OF THE STUDY

A canine experimental work was performed, to study osseointegration of cortico-cancellous bone allografts implanted in the lower femoral metaphysis. Particular attention was focused on observing the effects of autoclaving, used as a sterilizing method, on the osseointegration of bone allografts.

MATERIAL AND METHODS

Eighteen dogs were operated on and three groups were formed according to the type of graft: the first group included 4 autoclaved autografts and one animal, in which no graft was implanted. The second group included 11 frozen allografts in which 4 had been autoclaved. The third group included 2 animals, who received autoclaved allografts and were sacrificed at 10 months. In the first two groups, all animals were treated with the same protocol: graft stabilization using a plate, and specimen harvest at 4 months after surgery. In the third group, graft stabilization was obtained by press-fit only, and no plate was used.

RESULTS

Overall roentgenographic results were satisfactory, suggesting graft fusion with the host. Histological results were inferior to roentgenographic results, and showed graft resorption, but only some signs of bone formation at the periphery of the graft.

DISCUSSION

Roentgenographic results appeared optimistic, when compared to histological results. This suggests that roentgenographic results should not be considered as a reliable criteria for graft osseointegration. Despite favorable experimental conditions (cortico-cancellous graft implanted in the metaphyseal region, in a loaded segment of the skeleton, optimum graft stabilization using lateral plating), histological results were poor. New bone formation was observed at the periphery of the graft, but the major part of the graft remained fibrous. No difference was found between autoclaved and non autoclaved allografts in this small series.

CONCLUSION

These preliminary results suggest that autoclaving does not impair osseointegration of frozen bone allografts, which anyway remains incomplete.