Vascular changes caused by the Küntscher type of nailing; an experimental study in the rabbit.

Iii the Nuffield Orthopaedic Centre investigations of the blood supply of bone have been pursued for some time, and methods for the visualisation of the vessels have been published (Trueta 1953a, 1953b, Trueta and Harrison 1953, Harrison, Schajowicz and Trueta 1953). Part of this research entailed a study of the vascular pattern of fracture callus, and the results of this work are now being prepared for publication. Among the methods used in this investigation was suppression of one or other of the three main vascular sources of supply to the long bones (periosteal, metaphysial-epiphysial, and medullary) because it was known that the interruption of one or two of these sources stimulates those that remain to take over after a varying interval, an effect that is being used in this Centre to stimulate bone growth (Trueta 1950, 1952, l953c, l953d). I)uring the course of the general investigation into the blood supply of callus the hypothesis was advanced that overproduction of periosteal callus, which has been reported occasionally in man after K#{252}ntscher nailing (K#{252}ntscher 1940, 1941), could be explained by periosteal vascular proliferation after damage to the nutrient artery by the nail. During the whole of the research on the blood supply of callus special attention was paid to that possibility, and the results of this investigation have been separated from the main body of data collected on the healing of fractures and constitute the present publication. In the experimental animal, if the circulation of the bone marrow and that of the periosteum are interrupted, an increase in blood flow through the metaphysial vessels is usually observed. On the other hand, if the circulation through the nutrient artery and metaphysial vessels is interrupted, it is the periosteal blood flow which increases. During the course of the present work it was also observed that the proliferation of the periosteal vessels was always followed by new bone formation. When the blood flow through the nutrient artery was interrupted it was noticed that approximately the inner two-thirds of the cortex became ischaemic and subsequently necrotic, but that the outer third always remained alive, indicating that the main blood supply of the outer third of the cortex came across the periosteum. Contrariwise, when the periosteum was stripped and kept detached from the cortex by the interposition of an isolating polythene membrane, the circulation through the nutrient artery having been preserved, only the outer third of the cortex became the site of irregular ischaemia and a large periosteal bone (involucrum) formed round the whole shaft (Figs. I to 3). The correlation between vascular proliferation of the periosteum and bone formation seemed to indicate that the K#{252}ntscher method of bone nailing operates through the production of persistent ischaemia of the nutrient artery, in which case vascular proliferation of the periosteum would be responsible for the deposit of new layers of periosteal bone. In the original papers by K#{252}ntscher(1940, 1941) and in successive observations by Lauritzen (1949), Erlich (1943), B#{246}hler (1948) and others there is a diversity of opinion about the merits of the