alternate layers of bandages wet with silicate of soda and plaster of Paris, which is very durable, and has yielded excellent results. After it has been worn for some time, a year or more, the bone remains in place.

Of late years excision of the head of the femur has been done in old cases. Krönlein mentions a case by Roser, in 1874, and Heusner' reports a successful result in a girl twenty years old. In the latter case the dislocation was bilateral, and gave no special trouble until the age of seventeen, when the left hip became painful, and gradually grew so much worse that relief was sought in the hospital. The deformed head of the femur was removed, and the upper end of the femur fixed against the acetabulum, after the latter had been made deeper by chiselling.

2

Margary, of Turin, reported at the Congress at Copenhagen, in 1884, a case in which he had deepened the cotyloid cavity by chiselling, replaced the head of the femur in it, and had made a new capsule out of portions of the old one and of the periosteum of the ilium. The patient died of pyæmia. According to Da Paoli, Margary abandoned the method in favor of excision of the head. Paoli thought the results of the latter so defective that he again tried arthrotomy, with the addition of measures designed to increase the local reaction and thus favor a better development of a new acetabulum. He deepened the cotyloid cavity by chiselling, and diminished the size of the head, and fastened the latter in place by driving a nail from the outer aspect of the trochanter through the neck and head into the acetabulum, and left it in place twenty-five days. The operation was followed by fever and suppuration, but the patient recovered, and the shortening of nine and a half centimetres was permanently overcome. He thinks the most suitable age is between the eighth and twelfth years.

Congenital dislocations of other joints, except the knee, have rarely received any treatment. Malgaigne mentions a case of infraspinous dislocation of the shoulder in a girl sixteen years old, treated by Gaillard by traction; the head of the humerus was brought to the glenoid cavity and finally, after two recurrences of the displacement, retained there.

In a case quoted above, Mitscherlich excised the elbow for the relief of the disability consequent upon a congenital dislocation of the upper

end of the radius.

In dislocations of the tibia forward, with extreme hyper-extension of the knee, a complete cure has several times been effected by forcible straightening of the limb and retention for a short time by splints.

Heusner: Centralblatt für Chirurgie, 1884, p. 751.

2 Margary quoted in Dict. Encyclopédique des Sciences Méd., art. Hanche, p. 219. 3 Da Paoli: Centralblatt f. Chirur., 1887, p. 336,

Malgaigne: Des Luxations, p. 569.

CHAPTER X.

SPONTANEOUS DISLOCATIONS.

THESE are dislocations which have occurred without the introduction. of a recognizable traumatism. It is generally held that some of the constituent parts of the joint must have previously been so altered by disease as to facilitate the occurrence; but while this preliminary change does doubtless occur in the great majority of cases, yet there is reason to think that spontaneous dislocation may take place without it, through the continuous action of the muscles, when the limb has been long kept in a favorable position. Roser' says he has seen, in three cases, spontaneous dislocation of the hip produced by the reflex muscular contractions excited by pressure on the anterior portion of the spinal cord in patients affected with kyphosis and consequent paralysis. The dislocations occurred slowly, without pain or swelling of the region, and without a sign of coxitis.

The term "spontaneous," although not entirely free from objection, is in general use, and is usually preferred to the others that have been proposed, such as pathological, symptomatic, inflammatory, and consecutive or secondary. Volkmann2 has classified them according to the primary changes which precede and facilitate their occurrence, as dislocations, 1st, by distention; 2d, by destruction; 3d, by deformity; including in the first those cases in which the joint has become loose through distention of its capsule and ligaments by an effusion within it, as in the eruptive fevers, rheumatic fever, pyæmia, and the puerperal state; in the second those in which the shape of the articular end of the bone has been changed by caries, as in hip-joint disease; and in the third those in which the shape has been changed by non-suppurative disease, as in arthritis deformans. To these may be added a 4th class, seen mainly in adolescents, in which the shape or growth of the bones has been so modified by the effects of pressure, muscular effort, or gravity that a permanent displacement takes place; and a 5th, “paralytic" or "myopathic," in which the dislocation is made possible by paralysis of some or all of the articular muscles, and is somtimes effected by the contraction of those which have not been paralyzed.

Although the propriety of applying the term dislocation to a change in the relations of two bones whose corresponding articular portions have already been destroyed has been questioned, and although the change of place does not come within the definition of dislocation previously given, and although the condition has but little in common with traumatic dislocations, either in symptoms or in treatment, yet the term has been

1 Roser: Centralblatt f. Chirurgie, 1885, p. 569.

2 Volkmann: Pitha and Billroth's Chirurgie, vol. ii. part 2, p. 658.

almost universally accepted and retained in preference to the proposed substitutes.

In all these varieties the immediate cause of the dislocation is the action of gravity or muscular contraction.

Dislocations by distention (Volkmann).-Concerning the pathology of this class but little is known by direct examination, because of the lack of autopsies, but the clinical history is well established. The joint by far the most frequently involved is the hip; a few cases have been observed at the shoulder and knee. In the most common form the course of the symptoms is as follows: A patient is attacked by febrile articular rheumatism or acute mono-articular arthritis; the pain is great, the limb assumes a faulty position; after a few days the pain suddenly ceases, and on examination the region of the affected joint is found to present a deformity similar to that which characterizes a traumatic dislocation. If the condition is left without treatment, the inflammation comes to an end without leaving either osteitis or suppuration, but with persisting deformity; if, on the other hand, the dislocation is reduced, the deformity is thereby entirely removed, and in time complete recovery is obtained.

In other cases the dislocation takes place in the course of some of the eruptive fevers or other febrile condition, sometimes without previous notable pain in the joint and without the knowledge, at the time, of the patient. William Keen' collected forty-three cases of arthritis occurring as a complication of typhoid fever, in thirty of which dislocation took place, twenty-seven times at the hip, twice at the shoulder, and once at the knee.

It thus appears that these dislocations resemble those that are traumatic by their sudden occurrence, the absence of any lesion of the bones, and the possibility of immediate and permanent reduction with complete restoration of function.

The following cases taken from Verneuil's paper will show the details. Obs. II. (loc. cit., p. 783). A young and healthy woman was attacked in 1845 by acute articular rheumatism after exposure to cold; the pain was severe, especially in the right hip, but she was at first able to walk, although with a marked limp. At the end of the second week the pain in the hip suddenly ceased almost entirely, and recovery was thought to be at hand. A few days later she left the bed, but limped so badly that she could scarcely take a step without crutches. Some time later Verneuil was led to examine the hip, and was astonished to find marked deformity of the region with displacement of the head of the femur. The dislocation was not reduced, and when the patient was last examined, ten years later, the head of the femur could be still more distinctly felt in the external iliac fossa thinly covered by the atrophied gluteal muscles.

Obs. I. (loc. cit., p.782). A healthy girl, ten years old, had typhoid fever in July, 1883. During convalescence an attack of generalized rheumatism (or pseudo-rheumatism) occurred, ultimately localizing itself in the left foot and hip, with great pain, high fever, and considerable swelling of

1 Verneuil, in Bull. de la Soc. de Chirurgie 1883, p. 781.

2 Keen: Toner Lectures, Smithsonian Institute, April, 1875.

the affected joints; very faulty attitude of the limbs and pelvis. On the 11th or 12th day the pains suddenly ceased, and the child, which until that time had remained lying on the right side with the body and all the joints of the lower limbs flexed, was able to sit up in bed and allowed an examination. This examination revealed considerable shortening of the left lower extremity. Verneuil, called in consultation, easily recognized a dislocation of the femur upon the dorsum of the ilium. On the 6th day after that in which the dislocation was presumed to have occurred, chloroform was given, the diagnosis confirmed, reduction easily made, and the child placed in a Bonnet gutter. At the end of another fortnight all swelling and sensitiveness had disappeared, and a complete recovery was effected.

Obs. VIII. (loc. cit., p. 787). A healthy young girl was attacked by very acute, generalized, articular rheumatism; both knees were affected, the left more than the right. Since flexion of the leg upon the thigh was the attitude that gave most relief, it was maintained by means of a large cushion placed transversely under the leg. One morning marked deformity of one of the knees was noticed, consisting in a subluxation characterized by considerable prominence of the femoral condyles and patella, and displacement of the head of the tibia upward and backward, There was also flexion of the joint at a right angle, marked tumefaction, great sensitiveness to pressure, tension of the skin, etc. The other knee was a little swollen and contained some liquid, but had preserved its form. The patient declared that the displacement occurred suddenly during the preceding night, after a sudden start and energetic muscular contraction.

Verneuil recognized the tension of the flexor muscles, which contracted sharply at the slightest attempt to straighten the limb. He gave chloroform and easily reduced the displacement, noticing at the same time that all the femoro-tibial ligaments were very notably relaxed. The limb was placed in a splint in a position of almost complete extension, and afterward in an immovable dressing. The patient left the hospital cured of the rheumatism but walking with hesitation because of the weakness of the limb, although the knee had regained its natural size and shape.

The presence of a large effusion in the joint and the elongation of the ligaments have been assumed by all observers, and the actual presence of an effusion of some amount has been demonstrated in some of the exceptional cases, knee and shoulder, where such demonstration was possible. On the supposition of this effusion and of the relaxation of the ligaments produced by it, the production of the dislocation has been explained. Verneuil has further called attention especially to the unopposed contraction of certain muscles as the immediate cause. Some post-mortem observations have shown great distention of the capsule of the hip-joint in some cases (six ounces in Lerinser's case'), and great elongation of the ligamentum teres in others (Stanley, Hutton), but the latter may well have been the effect of the dislocation rather than its cause, and it does

Quoted by Volkmann, loc. cit.

2 Stanley Med. Chirurg. Trans., vol. 24, p. 123.

not appear in the histories that the dislocations occurred in the manner now in question. Theoretically speaking, a rapid effusion within the joint should serve rather to hold the bones more firmly together by making the capsule tense, unless the latter is loose enough to circumscribe a sphere whose diameter is greater than the distance between the fixed points of the capsule on the two bones, and it does not appear that this is the case in all positions of the hip-joint. Relaxation of the capsule and ligaments would then, on this theory, be a necessary preliminary to the dislocation.

Bonnet and Parise showed that by forcible injection of liquid into the cavity of the hip the articular surfaces could be separated for a distance of from three to six millimetres, one-eighth to one-quarter inch. The details of these experiments are not before me, but it seems probable that the separation existed only when the limb was flexed and the Y ligament thereby relaxed, for, according to Tillaux,' who repeated Parise's experiments, the injection causes the limb to become flexed. The flexed position relaxes the Y ligament, and if the capsule is filled with liquid the head of the femur can leave the cotyloid cavity without creating a vacuum, for the liquid takes its place, and thus a great obstacle to dislocation, atmospheric pressure, is removed. If it is remembered that these dislocations are always backward upon the dorsum of the ilium, and are preceded by the long maintenance of the limb in the position of flexion, adduction, and inward rotation which so greatly favors the occurrence of this dislocation, and that the muscles are stimulated to contraction by the pain of the arthritis, it does not appear improbable that this contraction is not only the immediate but also the preponderant cause of the accident, and that the arthritis favors it not by overstretching the ligaments but only by supplying an amount of liquid that removes the obstacle created by atmospheric pressure. These two conditions, pain and effusion, would explain why the dislocation does not also occur in the course of adynamic diseases in which the limb often remains for a long time in the flexed position.

Certainly the theory of the production of the dislocation by simple overdistention is incompatible with the easy reduction and maintenance of the reduction noted in several cases. It was unfortunate for some of the patients that their surgeons held to this theory, and were logical enough to refrain from attempting reduction and to leave the patients permanently crippled.

A few cases have been observed in which an acute purulent arthritis has been followed by dislocation; but in such cases it is always possible that the capsule has been in part destroyed by the suppuration.

Paralytic or "myopathic" dislocations, which are included by Krönlein in the preceding class, are observed especially at the shoulder. The humerus is held up and kept in contact with the glenoid cavity by the tonicity of the attached muscles, and when this tonicity fails the weight of the limb causes separation of the bones and subluxation or complete dislocation. The cavity of the joint, thus enlarged, is filled by

1 Tillaux: Anatomie topographique, p. 1082.