ROENTGENOGRAPHIC AND HISTOLOGICAL OBSERVA TIONS OF AUTOCLAVED AND NON-AUTOCLAVED ALLOGRAFTS IN CANINE DISTAL FEMORAL METAPHYSIS

Purpose of the study A canine experimental work was performed, to stud y osteointegration of cortico-cancellous bone allografts implanted in the lower femoral metaphysis. Particular attention was focused on obse rving the effects of autoclaving, used as a sterilizing method, on the osteointegration of bone allografts. Material and methods Eighteen do gs were operated on and three groups were formed according to the type of graft: the first group inclued 4 autoclaved autografts and one ani mal, in which no graft was Implanted. The second group included 11 fro zen allografts in which 4 had been autoclaved. The third group include d 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 harves t at 4 months after surgery. In the third group, graft stabilization w as obtained by press-fit only, and no plate was used. Results Overall roentgenographic results were satisfactory, suggesting graft fusion wi th the host. Histological results were inferior to roentgenographic re sults, and showed graft resorption,but only some signs of bone formati on at the periphery of the graft. Discussion Roentgenographic results appeared optimistic, when compared to histological results. This sugge sts that roentgenographic results should not be considered as a reliab le criteria for graft osteointegration. Despite favorable experimental conditions (cortico-cancellous graft implanted in the meta region, in a loaded segment of the skeleton, optimum graft stabilization using l ateral plating), histological results were poor. New bone formation wa s observed at the periphery of the graft, but he major part of the gra ft remained fibrous. No difference was found betwen autoclaved and non autoclaved allografts In this smalt series. Conclusion These prelimin ary results suggest that autoclaving does not impair osteointegration of frozen bone allografts, which anyway remains incomplete.