Manual of Surgery Volume II Part 6

Dislocation of #both ends# of the clavicle has occasionally occurred from a severe crush. The ultimate result has been satisfactory, as one or other end has always healed in normal position, and the function of the arm has thus been maintained.

DISLOCATION OF THE SHOULDER

The shoulder is more frequently dislocated than all the other joints in the body taken together. This is explained by its exposed position, the wide range of movement of which it is capable, the length of the lever afforded by the humerus, and the anatomical construction of the joint--the large, round humeral head imperfectly fitting the small and shallow glenoid cavity, and the ligaments being comparatively lax and thin. The capsule of the joint is materially strengthened in its upper and back parts by the tendons of the supra- and infra-spinatus and teres minor muscles; while it is weakest below and in front, between the subscapularis and teres major tendons. It is here that it most frequently gives way and allows of the escape of the head of the bone.

The determining factor is probably that when the arm is abducted the neck of the humerus comes in contact with the tip of the acromion, and further abduction forces the head against the lower, weak portion of the capsule, which gives way.

The violence is usually transmitted from the hand or elbow, less frequently from the lateral aspect of the shoulder, the limb being usually abducted and the muscles relaxed and taken unawares. The head of the humerus, thus brought to bear on the weakest part of the capsule, ruptures it and pa.s.ses out through the rent. Dislocation is readily produced in an unconscious person--as, for example, in conducting artificial respiration in a patient suffering from opium poisoning, the arms being hyper-abducted to exert traction on the chest.

_Varieties._--Several varieties of dislocation are recognised, according to the position in which the head of the humerus finally rests (Fig. 17). The simplest of these is the _sub-glenoid_ variety, in which the head rests on the long tendon of the triceps, where it arises from the axillary border of the scapula just below the glenoid cavity. In almost all dislocations of the shoulder the head of the bone is at least momentarily in this position, but the sharp edge of the scapula and the rounded head are ill adapted to one another, and the position is not long maintained. The subsequent course taken by the humerus depends upon the nature and direction of the force, the position of the limb at the moment of injury, and the relative strength and capacity for effective action of the different groups of muscles acting upon the bone.

[Ill.u.s.tration: FIG. 17.--Diagram of most common varieties of Dislocation of the Shoulder.]

In the great majority of cases it pa.s.ses forward and medially, and comes to lie against the anterior surface of the neck of the scapula, under cover of the tendons of origin of the biceps and coraco-brachialis muscles, const.i.tuting the _sub-coracoid dislocation_. Much less frequently it pa.s.ses under cover of the pectoralis minor and against the edge of the clavicle--the _sub-clavicular_ variety. In rare cases the head pa.s.ses backward and lies against the spine on the dorsum of the scapula, beneath the infra-spinatus muscle--the _sub-spinous_ variety. Other varieties are so rare that they do not call for mention.

_Clinical Features common to all Varieties._--Dislocation of the shoulder is commonest in adult males; in advanced life the proportion of female sufferers increases. It is usually attended with great pain, and there is often numbness of the limb due to pressure of the head of the bone upon the large nerve-trunks. There is sometimes considerable shock. The patient inclines his head towards the injured side, and, while standing, the forearm is supported by the hand of the opposite side. The acromion process stands out prominently, the roundness of the shoulder giving place to a flattening or depression immediately below it, so that a straight-edge applied to the lateral aspect of the limb touches both the acromion and the lateral epicondyle. The vertical circ.u.mference of the shoulder is markedly increased; this test is easily made with a piece of tape or bandage and is compared with a similar measurement on the normal side--we lay great stress on this simple measure, as it is a most reliable aid in diagnosis. The head of the bone can usually be felt in its new position, and the axis of the humerus is correspondingly altered, the elbow being carried from the side--forward or backward according to the position of the head. The empty glenoid may sometimes be palpated from the axilla. In most cases, although not in all, the patient is unable at one and the same time to bring his elbow to the side and to place his hand upon the opposite shoulder (Dugas' symptom). Measurements of the length of the limb from acromion to lateral epicondyle are rarely of any diagnostic value.

The #sub-coracoid dislocation# (Fig. 18) is that most frequently met with. It usually results from hyper-abduction of the arm while the scapula is fixed, as in a fall on the medial side of the elbow when the arm is abducted from the side. The surgical neck of the humerus is then brought to bear upon the under aspect of the acromion, which forms a fulcrum, and the head of the bone is pressed against the medial and lower part of the capsule. In some cases muscular action produces this dislocation; it may also result from force applied directly to the upper end of the humerus.

[Ill.u.s.tration: FIG. 18.--Sub-coracoid Dislocation of Right Shoulder.]

The head leaves the capsule through the rent made in its lower part, and, either from a continuation of the force or from contraction of the muscles inserted into the inter-tubercular (bicipital) groove, particularly the great pectoral, pa.s.ses medially under cover of the biceps and coraco-brachialis till it comes to rest against the anterior surface of the neck of the scapula, just below the coracoid process. The anatomical neck of the humerus presses against the anterior edge of the glenoid, and there is frequently an _indentation fracture of the head of the humerus_ where the two bones come into contact (F. M. Caird). The subscapularis is bruised or torn, the muscles inserted into the great tuberosity are greatly stretched, or the tuberosity itself may be avulsed, allowing the long tendon of the biceps to slip laterally, where it may form an impediment to reduction. The axillary (circ.u.mflex) nerve is often bruised or torn, and the head of the humerus is liable to press injuriously on the nerves and vessels in the axilla.

The _clinical features_ common to all dislocations are prominent, although Dugas' symptom is not constant.

[Ill.u.s.tration: FIG. 19.--Sub-coracoid Dislocation of Humerus.

(Sir H. J. Stiles' case. Radiogram by Dr. Edmund Price.)]

_Treatment._--The guiding principle in the reduction of these dislocations is to make the head of the bone retrace the course it took in leaving the socket. The main obstacles to reduction being muscular contraction and the entanglement of the head with tendons, ligaments, or bony points, appropriate means must be taken to counteract each of these factors.

A general anaesthetic is an invaluable aid to reduction, and should be given unless there is some reason for withholding it. It is specially indicated in strong muscular subjects, and in nervous patients who do not bear pain well, and particularly when the dislocation has existed for a day or two. In quite recent cases, however, the surgeon may succeed in replacing the bone by taking advantage of a temporary faintness, or by engaging the patient's attention with other matters while he carries out the appropriate manipulations.

When an anaesthetic is employed, the patient should be laid on a mattress on the floor, or on a narrow, firm table; otherwise he should be seated on a chair.

_Kocher's method_ is suitable for the great majority of cases of sub-coracoid dislocation. (1) The elbow is firmly pressed against the side, and the forearm flexed to a right angle. The surgeon grasps the wrist and elbow and firmly _rotates the humerus away from the middle line_ (Fig. 20) till distinct resistance is felt and the deltoid becomes more prominent. In this way the rent in the lower part of the capsule is made to gape, and the head of the humerus rolls away from the middle line till it lies opposite the opening, rotation taking place about the fixed point formed by the contact of the anatomical neck of the humerus with the anterior lip of the glenoid cavity (D.

Waterston). (2) _The elbow is next carried forward, upward, and towards the middle line_ (Fig. 21); the humerus acting as the long arm of a lever on the fulcrum furnished by the muscles inserted in the region of the surgical neck, the head, which forms the short arm of the lever, is carried backward, downward, and laterally, and is thus directed towards the socket. (3) The humerus is now _rotated towards the middle line_ by carrying the hand across the chest towards the opposite shoulder (Fig. 22). The anatomical neck of the humerus is thus disengaged from the edge of the glenoid, and the head is pulled into the socket by the tension of the surrounding muscles.

[Ill.u.s.tration: FIG. 20.--Kocher's Method of reducing Sub-coracoid Dislocation--First Movement; Rotation of Arm away from Middle Line.]

[Ill.u.s.tration: FIG. 21.--Kocher's Method--Second Movement; Elbow carried forward, upward, and towards the Middle Line.]

[Ill.u.s.tration: FIG. 22.--Kocher's Method--Third Movement; Rotation of Arm towards Middle Line.]

A method of reduction has been formulated by A. G. Miller, which we have found to be quite as successful as Kocher's method. The limb is grasped above the wrist and elbow, the forearm flexed to a right angle, and the upper arm abducted to the horizontal (Fig. 23). While an a.s.sistant makes counter-extension and fixes the scapula, the surgeon gradually draws the arm away from the body till the head of the humerus is felt to pa.s.s laterally. The humerus is then rotated medially by dropping the hand (Fig. 24), and the bone gradually glides into the socket.

[Ill.u.s.tration: FIG. 23.--Miller's Method of reducing Sub-coracoid Dislocation--First Movement.]

[Ill.u.s.tration: FIG. 24.--Miller's Method of reducing Sub-coracoid Dislocation--Second Movement.]

In a certain number of cases reduction can be effected by _hyper-abduction_ of the shoulder with traction. The patient is laid upon a firm mattress, and the surgeon, seated behind him while an a.s.sistant fixes the acromion, slowly and steadily extends the arm until it is raised well above the head. In some cases the head of the humerus spontaneously slips into its socket; in others it may be manipulated into position by pressure from the axilla. This method is restricted to recent cases, as in those of long standing the axillary vessels are liable to be stretched or torn.

The method of reduction by traction on the arm with the heel in the axilla is only to be used when other measures have failed, as it depends for its success on sheer force.

_After-Treatment._--After reduction, the part is gently ma.s.saged for ten or fifteen minutes, a layer of wool is placed in the axilla, the forearm is supported by a sling, and the arm fixed to the side by a circular bandage. Ma.s.sage is carried out from the first, and movement of the shoulder in every direction except that of abduction may be commenced on the first or second day. The circular bandage may be dispensed with at the end of a week, and abduction movements commenced, and by the end of a month the patient should be advised to use the arm freely.

The #sub-clavicular dislocation# (Fig. 17) is to be looked upon as an exaggerated degree of the sub-coracoid rather than as a separate variety. It is produced by the same mechanism, but the violence is greater, and the damage to the soft parts more severe. The head pa.s.ses farther upwards and towards the middle line under cover of the pectoralis minor, resting under the clavicle against the serratus anterior and chest wall. The symptoms are usually so marked that they leave no doubt as to the diagnosis. The outline of the head of the humerus in its abnormal position is visible through the skin, and the shortening of the limb is more marked than in the sub-coracoid variety. The treatment is the same as for sub-coracoid dislocation.

#Sub-glenoid dislocation# (Fig. 17) is less frequently met with than the sub-coracoid variety, and almost always results from forcible abduction of the arm. The head of the humerus pa.s.ses out through a small rent in the lower and medial portion of the capsule, and rests against the anterior edge of the triangular surface immediately below the glenoid cavity, supported behind by the long head of the triceps, and in front by the subscapularis muscle. It is readily felt in the axilla. All the tendons in relation to the upper end of the humerus are stretched or torn, and the great tuberosity is not infrequently avulsed. There is sometimes bruising of the axillary nerve.

The projection of the acromion, the flattening of the deltoid, the increased depth of the axillary fold, and the abduction of the elbow are well marked; the arm is slightly lengthened, rotated out, and carried forward. It is reduced by the hyper-abduction method (p. 60).

#Sub-spinous Dislocation.#--Backward dislocation is usually termed sub-spinous, although in a considerable proportion of cases the head of the humerus does not pa.s.s beyond the root of the acromion process (_sub-acromial_) (Fig. 17). This dislocation is usually produced by a fall on the elbow, the arm being at the moment adducted and rotated medially, so that the head of the humerus is pressed backwards and laterally against the capsule, which ruptures posteriorly. All the muscles attached to the upper end of the humerus are liable to be torn, and the tuberosities are frequently avulsed. The long tendon of the biceps may slip from its position between the tuberosities, and prevent reduction or favour re-dislocation, necessitating an open operation.

In the milder cases the _clinical features_ are not always well marked, and on account of the swelling this dislocation is apt to be overlooked. In addition to the ordinary symptoms, the shoulder is broadened, there is a marked hollow in front in which the coracoid projects, and the arm is held close to the side with the elbow directed forward. The head of the bone may be seen and felt in its abnormal position below the spine of the scapula.

Reduction can usually be effected by making traction on the arm with medial rotation, and pressing the head forward into position, while counter-pressure is made upon the acromion.

_Prognosis._--The ultimate prognosis in dislocations of the shoulder should always be guarded. The axillary nerve may be stretched or torn, and this may lead to atrophy of the deltoid; or other branches of the brachial plexus may be injured and the muscles they supply permanently weakened. In a certain number of cases traumatic neuritis has resulted in serious disability of the limb. The movements of the shoulder-joint may be restricted by cicatricial contraction of the torn portion of the capsule and of the damaged muscles. A marked tendency to recurrent dislocation may follow if abduction movements are permitted before repair of the capsule has had time to occur.

#Dislocation of the Shoulder complicated with Fracture of the Upper End of the Humerus.#--In these injuries the dislocation is almost always of the sub-coracoid variety, and the most common fractures by which it is complicated are those of the surgical neck, the anatomical neck, or the greater tuberosity. The most common cause is a fall directly on the shoulder, and it seems probable that the head of the bone is first dislocated, and, the force continuing to act, the upper end of the humerus is then broken; or the two lesions may be produced synchronously.

When seen soon after the accident, the existence of the fracture of the humerus is liable to be overlooked, the condition being mistaken for dislocation alone, or for a fracture through the neck of the scapula. On careful examination under an anaesthetic, however, it is observed that not only is the head of the humerus absent from the glenoid cavity, but that it does not move with the rest of the bone, abnormal mobility and crepitus are recognised at the seat of fracture, and the upper arm is shortened. The extravasation in the axilla is usually greater than that accompanying a simple dislocation, and the pain and shock are more severe. A fracture through the neck of the scapula alone is readily recognised by the ease with which the deformity is reduced, and the way in which it at once recurs when the support is withdrawn. In many cases it is only by the aid of a radiogram that an accurate diagnosis can be made (Fig. 25).

[Ill.u.s.tration: FIG. 25.--Dislocation of Shoulder with Fracture of Neck of Humerus.

(Sir Robert Jones' case. Radiogram by Dr. D. Morgan.)]

_Treatment._--Unless the dislocation is reduced at once, the movements of the arm are certain to be seriously restricted, and painful pressure effects from excess of callus are liable to ensue. An attempt should first be made, under anaesthesia, to replace the head in its socket, by making extension on the arm in the hyper-abducted (vertical) position, and manipulating the upper fragment from the axilla.

On no account should the lower fragment be employed as a lever in attempting reduction. When reduction by manipulation fails, recourse should be had to an open operation. The upper fragment should be exposed by an incision over its lateral aspect, and made to return to the socket by using Arbuthnot Lane's levers or M'Burney's hook, or a long steel pin may be inserted into the fragment to give the necessary leverage.

Reduction having been accomplished, the fracture is adjusted in the usual way, advantage being taken of the open wound, if necessary, to fix the fragments together by plates. The best position in which to fix the limb is that of abduction at a right angle. Ma.s.sage and movement should be commenced early to prevent stiffness of the joint.

When it is found impossible to reduce the dislocation, it is usually advisable to remove the upper fragment.

The method of allowing the fracture to unite without reducing the dislocation, and then attempting reduction, usually results in re-breaking the bone, or else in failure to replace the head in the socket, and has nothing to recommend it.

#Old-standing Dislocation of the Shoulder.#--It is impossible to lay down definite rules as to the date after which it is inadvisable to attempt reduction by manipulation of an old-standing dislocation of the shoulder. Experience of a hundred cases in Bruns' clinic led Finckh to conclude that, provided there are no complications, reduction can generally be effected within four weeks of the accident; that within nine weeks the prospect of success is fairly good; but that beyond that time reduction is exceptional.

The patient is anaesthetised, and all adhesions broken down by free yet gentle movement of the limb. The appropriate manipulations for the particular dislocation are then carried out, care being taken that no undue force is employed, as the humerus is liable to be broken. If these are not successful, they should be repeated at intervals of two or three days, as it is frequently found that reduction is successfully effected on a second or third attempt.

Should manipulative measures fail, it may be advisable to have recourse to operation if the age of the patient and his general health warrant it, and if the condition of the limb is interfering with his occupation or involves serious disability. If operation is deemed advisable, a few days should be allowed to elapse to permit of the parts recovering from the effects of the manipulations. The joint is freely exposed, the capsule divided, the head of the bone freed and returned to the glenoid cavity. It is sometimes so difficult to replace the head of the bone that it is necessary to resect it and aim at the formation of a new joint, an operation which usually yields satisfactory results.

#Habitual or Recurrent Dislocation.#--Cases are occasionally met with in which the shoulder-joint shows a marked tendency to be dislocated from causes altogether insufficient to produce displacement under ordinary circ.u.mstances. This condition is usually met with in young women, and, in some cases at least, appears to be due to too early and too free movement of the joint after an ordinary dislocation, so that the capsule is stretched and remains lax. In some cases it would appear that the liability to dislocation is due to some structural defect in the joint, and under these conditions both sides are sometimes affected, and the accident is not attended with the usual pain and disability either at the time or after reduction. The facility and frequency with which dislocation recurs render the limb comparatively useless, and may seriously incapacitate the patient. We have had cases under observation in which dislocation resulted from the hyper-abduction of the arm in swimming, from throwing the arms above the head in dancing and in gymnastic exercises, and even in "doing" the hair.

The _treatment_ consists in preventing the patient making the particular movements which tend to produce the dislocation. These are chiefly movements of hyper-abduction and overhead movements; we have found an apparatus consisting of a belt applied around the thorax, and fixed to another around the upper arm by a band which pa.s.ses above the axillary fold of the dress, useful in restraining these movements. If these measures fail, it may be advisable to have recourse to operation; this may consist in tightening up the capsule, the results of which are said to be uncertain, or in detaching a portion of the deltoid or subscapularis muscle and st.i.tching it beneath the joint to cover and strengthen the weakened portion of the capsule. It is suggestive that in performing this operation no rent in the capsule is discovered.