Studies of the vascularisation of bone grafts.

A copious literature, including many accounts of experimental studies on bone grafting and on the different behaviour of autogenous, homogenous and heterogenous implants is already available. Among these contributions only a few are dedicated to describing the vascular pattern of the bed and graft and most of these give only scanty or unsupported evidence of the vascular behaviour in bone grafting. Marchand (1901) seems to have been the first to study the vessels in transplanted bone; only a few isolated sections of each graft were studied in dogs, and no photographic records were obtained. L#{228}wen(1909) described the vessels in a human tibial graft after excision ofa sarcoma of the humerus, and showed a drawing of the specimen. Nemilow investigated the part played by the periosteum in the early vascular penetration of the graft; so far as we know from the quotation of Petrow (1914), the most important result of his eight experiments in rabbits was to show that in the first six days the transplanted periosteum was vascularised, whereas no vessels were to be seen in the bone without periosteum. Bertini (1926) used only autogenous bone to study the behaviour of the vessels near and in the holes he had made in the bone of rabbits. Unfortunately only four photomicrographs with very little magnification were given in his paper. Rubaschewa and Priwes (1932) studied the macroscopic modifications of the vascular network around the graft in dogs of various ages, particularly in the periosteum; no account was given of any fine vessels or of the microscopic characteristics of the graft. May (1937) observed the macroscopic modifications of the vessels in a radius experimentally transplanted, without giving any details of the vessels. The two main contributions based on recorded experimental data will now be considered. Hancox (1947) observed directly the vascularisation of small grafts transplanted to the chorio-allantoic membrane of the chicken; the size and the type of the fragments (frontal bone) and of the bed used seem too far removed from clinical practice in orthopaedic surgery to allow any definite conclusion to be drawn from this work. Kiehn et al (1952) followed the evolution of the vascular pattern in grafts transplanted in transparent chambers ; here also, as the authors pointed out, the bed and the size of the fragments were quite unusual and this may explain the different rate of vascular penetration compared with that which we have found. Apart from these few papers, some hundreds of the two thousand odd works relating to bone grafts mention the vessels; yet only from a few of them is it possible to gain any information on the vascular pattern and the rate of penetration. Trying to assess from these investigations the rate of penetration of the vessels in autogenous grafts we find the following. Hancox (1947) saw functioning vessels in a graft after only five hours from its implantation; Nemilow (quoted by Petrow 1914) found the injected substance in the vessels of periosteum transplanted two days previously, and Gallie and Robertson (1919) after the