MICROVASCULAR TRANSPLANTATION OF PHYSEAL ALLOGRAFTS

We compared growth in vascularised allograft transplants, autografts a nd in non-operated physes in rabbits immunosuppressed with cyclosporin A and in non-immunosuppressed animals. Molecular haplotyping was unde rtaken before operation to ensure allogenicity. Postoperative bone sca ns and fluorochrome labelling were used to confirm physeal vascularity , The animals were killed at three or five weeks. Proximal tibial phys eal autografts, with or without cyclosporin A, or allografts with cycl osporin A, grew at similar rates to the physes of non-operated rabbits , All the operated physes grew at rates signicantly greater than their contralateral controls. Tc-99m-MDP bone scans accurately predicted th e viability of the epiphyseal plate, Quantitative histomorphological a nalysis of the heights of the physeal proliferative and hypertrophic z ones showed that successful physeal transplants have a normal appearan ce, but when unsuccessful have thickened hypertrophic zones compatible with physeal ischaemia. We discuss the significance of these results in relation to the transplantation of physes in children.