Fundamental Factors for Delay and Non-union in Fractures *

At the present time, as is evidenced by the research being done on bone healing, there is apparently a renewed interest in the causes of failure of broken bones to unite. It is always well at such a time to go back to the fundamentals of the subject being investigated to be sure that we have not forgotten our essential physiological processes. It might be pertinent, at the beginning, to inquire, "What is a fracture?" In asking this question it is not suggested that even the veriest tyro in medicine does not know the answer but I do wish to bring to mind what we, from our constant contact with pathological processes, are apt to forget-that a fracture is pathological only in its occurrence and that normally the healing process is akin to union of the soft tissue either by first intention or by fibrous tissue. It is the normal repair to injury without the interposition of a true pathological process. A fracture occurs as the result of the imposition upon unfractured bone of a force greater than it was designed to bear. It is usually a violent force. It is hardly conceivable that any fracture could occur without hemorrhage. Except in compounded fractures, the hemorrhage remains within the tissues and varies within wide limits. The hemorrhage stops when the pressure created by the escape of blood into the tissues is sufficient to counterbalance the pressure in the bleeding vessel or vessels. The presence of the blood in the tissues is pathological. It cannot there perform its main functions and it is disposed of normally in one of two ways-by absorption or by organization. If the blood supply is efficient the hemorrhage is absorbed but if the blood supply is poor the blood remains in the tissues where a series of processes, called organization, occur. Under certain conditions practically all the hemorrhage is absorbed; under others the degree of absorption and organization may vary. If organization occurs its final form may take that of any of the tissues arising from the mesodermal layer.