INCORPORATION OF DEVITALISED AUTOGRAFTS IN DOGS

Segments of the tibial diaphysis from 24 adult dogs were reimplanted a fter extracorporeal autoclaving or gamma-irradiation. Fixation was by interlocking intramedullary nailing, or plating, The dogs were killed after 36 weeks and the tibias examined. Bony union was seen in 46 of t he 48 contact areas. Microangiography and Tc-perfusion scans demonstra ted complete revascularisation of all the grafts. Biomechanical tests showed defective union with increased bending and decreased stiffness compared to normal controls. Fluorescent microscopy confirmed restitut ion of Haversian systems and slow replacement of the graft by lamellar bone containing viable osteocytes.