Eighty operative procedures in sixty-one patients are reported. Sixteen (in fourteen patients) were followed by complications, due directly to os purum in six cases. These six (10 per cent.) included two spine fusions, three posterior bone blocks, and one intramedullary splint. All complications totaled 20 per cent., with none constituting a major factor in the end results. The rate of fusion appeared to be slightly slower than in control cases using autogenous implants. The amount of fused bone in which os purum was used was somewhat less, as to size and thickness, than in the autogenous controls. In all but six instances, the os purum seemed to be tolerated practically as well as autogenous bone, and continued to serve its purpose even in the presence of a frank wound infection. As a result of this experience with os purum implants, the following conditions became quite clear to the author:
1. All osteogenic sources about the recipient bed must be carefully preserved.
2. Complete fixation of the parts must follow implantation with os purum.
3. Complete asepsis with the Lane technique is preferred. (In many of the author's cases, sulfanilamide powder was sprinkled into the wound before it was closed, without any appreciable slowing in the rate of acceptance.)
4. Intramedullary fixation can be used in selected cases without complicating the result appreciably.
5. The implant should remain in its bed for sixteen weeks, even if there are signs of intolerance or of foreign-body reaction. By that time it has served its purpose and can be removed.
6. The implant should be shaped to the desired size as carefully as possible. An excess amount of os purum appears to be a long time in absorbing, and may produce a slight serous discharge for several months at the site of the wound. This occurred, however, in a very limited number of cases. Removal of the implant, or of the excess of the implant, will not interfere with bone formation, and the wound mill close promptly.
7. Os purum implants, unless under physiological stress and strain and surrounded by osteogenic tissues, will be resorbed and disappear.
The author believes that the use of os purum has its place and constitutes a satisfactory material for the orthopaedic surgeon. For the duration of the War, however, it appears that os purum cannot be obtained from Sweden. The supply in this country is almost exhausted. Perhaps some biochemical manufacturer may see fit to produce os purum in this country, if this can be done under trade agreements.
Leriche and Policard pose three propositions to be fulfilled for the future of bone surgery: (1) Can one influence the formation of bone? (2) Can one influence bone resorption? (3) Can one model new ossifications? The use of Orell's especially prepared bone introduces a substance which promises to go far toward answering these three interesting questions.