FRACTURES OF THE PATELLA.
During the active period of middle life the patella is the bone most frequently broken by muscular violence. In many cases it is practically cracked over the condyles, as one would crack a piece of wood over the knee. If direct force be applied, as by a fall, in connection with the above, the effect is even more marked. In such cases the fracture is sometimes comminuted [(Fig. 325]), or the line of fracture may run more or less perpendicularly rather than horizontally. Ordinarily, however, these fractures are transverse, while the upper fragment is pulled upward, sometimes to a considerable distance, by the powerful extensors of the leg. When the fracture runs vertically the displacement is very slight. Occasionally these fractures are compound, a most undesirable complication, since the knee-joint is thus exposed to infection, from which it suffers unless first attention be prompt and scientific. There is usually sufficient hemorrhage to distend the joint cavity, and it may at first be quite impossible to bring the fragments near enough to each other to get crepitus, but the loss of the power of extension and the evident gap between the fragments will serve to make diagnosis positive, at least in all transverse fractures. A vertical fracture without much separation is a milder form of injury which may be regarded in a much more favorable light ([Figs. 326], [327] and [328]).
In these transverse fractures it is rare that bony union can be secured by non-operative methods. This is not only because of the difficulty in maintaining parts in apposition, but because it is notably the case that fragments of periosteum or other tissue drop in between bony surfaces and tend to prevent their actual contact, no matter how firmly they may be pressed toward each other. Osseous union then may occur without operation, but is rare. The best that can be expected is fibrous union, the intervening fibrous band being short or long, according to the success met with in treatment and to the amount of strain later put upon it by too early use of the limb. Even with two inches of fibrous tissue intervening patients are not completely disabled. The usefulness of a limb under these conditions, however, is seriously impaired. Something will depend, also, on the extent to which the joint capsule and the aponeurosis terminating the vasti muscles may have suffered.
Treatment.
—The non-operative treatment consists in placing such a limb upon a single inclined plane, for the purpose of relaxing the quadriceps extensor group. In this position the limb should be maintained for at least from ten to fourteen days. Some expedient should be added, so soon as swelling has subsided, by which the upper fragment can be coaxed downward toward its fellow. A neatly molded splint, formed out of gutta-percha or of plaster of Paris, may be fitted to the thigh above the fragment, held in position, and then drawn downward by elastic traction on either side of the leg, the principle of traction being thus given a special application. Something of this kind should be done if the fragments are to be approximated to each other.
Fig. 325
Fig. 326
Fig. 327