It has usually been stated that, when pieces of the periosteum are transplanted, they proceed to the formation of bone. This is only true in regard to the deep layer of the periosteum, or more properly the subperiosteal layer. The periosteum proper, consisting of fibrous tissue, is incapable of producing bone. On the other hand the bone itself, or the tissue in its various cavities, as well as the endosteum, is capable, as we have seen, of forming bone. Hence a transplantation of periosteum, including the subperiosteal layer, or of pieces of bone, may be followed, not only by survival of the pieces, but by new-formation of bone from them.

Transplantation of the periosteum is not an uncommon pathological process. The periosteum may be raised by the accumulation of pus beneath it, or it may be stripped off by an injury, and in that case, if the ossifying layer be preserved, ossification occurs. This fact is sometimes taken advantage of by surgeons, who detach the periosteum, and displace it with a view to the ultimate formation of bone. The Transplantation of bone itself has been demonstrated chiefly by Macewen. It is apparent from his observations that bone, contrary to what might be expected, has great power of retaining its vitality when detached from its connections. A piece of bone transplanted will, even when of considerable size, survive long enough to acquire fresh vascular connections, and, in accordance with what occurs in transplanted structures generally, it will often proceed to grow in its new position. Accidental transplantation must often occur in connection with fractures, and the detached piece of bone, as mentioned above, usually survives.

United Fracture of tibia and fibula with displacement.

Fig. 279. - United Fracture of tibia and fibula with displacement. The ends ride over each other, and there is much permanent new-formed bone to unite them. The tibia and fibula are also united by bone.

Advantage has been taken of these facts in an ingenious way by Macewen. In the operation of trephining, a circular piece of bone, often of considerable size, is removed from the skull. This piece of bone may be preserved during a subsequent operation on the brain and re-implanted in the gap, at the close of the operation. If septic contamination is prevented, the bone survives and grows into its place, tilling up by new-formed tissue the interval made by the saw.

Still more interesting are the results of transplantation in the treatment of a case in which the shaft of the humerus had been lost by necrosis. In this case pieces of bone removed from the femurs of other patients (in the operation of Osteotomy) were broken up into small pieces and inserted among the muscles into a sulcus where the shaft of the bone should have been. By three operations the bone was restored to the extent of four and a quarter inches, and there was a subsequent growth in the course of seven years of an inch and three-quarters. This case demonstrates that pieces of the bone removed from one person to another not only survive but grow in their new position. Transplantation from one of the lower animals does not succeed, the foreign bone acting as an irritant.

Literature

Malgaigne, Traite des fract. et luxat., 1855; Gurlt, Handb. d. Lehre v. d. Knochenbriichen, 1862; Krafft, in Ziegler und Nauwerk's Beitrage, 1884; Ollier, Traite de la regeneration des os, 1867; Macewen, Phil, trans, of Roy. Soc, 1881, and Annals of Surg., 1887; Macgregok, Jour, of Anat. and Phys., xxvi., 220; Ogston, Med. Chronicle, Nov., 1888.