DISLOCATION OF BOTH BONES FORWARDS.

This accident is the result of a severe blow upon the back of the flexed elbow, or of forcible traction-as when the arm is caught in machinery. Both bones are displaced forwards, and the olecranon lies in front of the articular surface of the humerus. So severe an injury is necessary for the production of the dislocation that all the ligaments of the joint are usually ruptured and the dislocation is very likely to be compound.

Treatment.-Reduction is effected under an anesthetic by fixing the upper arm and then flexing the elbow to its utmost limit and at the same time pushing the forearm downwards and backwards. As soon as the olecranon reaches the lower part of the articular surface of the humerus it clears its edge and the bones slip readily into position. The after-treatment is similar to that for dislocation of both bones backwards (see p. 39).

DISLOCATION OF EITHER BONE ALONE.

The radius is dislocated alone much more frequently than is the ulna.

DISLOCATION OF THE ULNA ALONE.

This is such a rare injury that doubts have been thrown upon its occurrence, and more exact information-which is only to be obtained by radiography is required before much can be said about it. The dislocation is backwards; the orbicular ligament is ruptured, but the head of the radius remains in its normal position with regard to the lower end of the humerus.

Treatment. The treatment will be similar to that for dislocation of both bones backwards (see p. 38).

DISLOCATION OF THE RADIUS ALONE.

It is not uncommon for the head of the radius to be dislocated forwards whilst the ulna retains its normal position. The accident usually occurs in children, and generally results either from falls upon the outstretched hand or from the common practice of lifting children by the hands. A severe strain is thus thrown upon the orbicular ligament, which may rupture, or the head of the bone may escape upwards in front of the outer condyle of the humerus. The accident may also be caused by a direct blow upon the upper end of the radius, such as would occur in falls upon the outer side and back of the elbow. The dislocation renders flexion beyond a right angle mechanically impossible on account of the apposition of the head of the radius to the front of the articular surface of the humerus. The forearm is usually in a position midway between pronation and supination.

Treatment. There is often much difficulty in replacing the head of

the bone, owing to the obstacle offered by the orbicular ligament, which may fall into and fill up the lesser sigmoid cavity of the ulna. Moreover, after successful reduction, the head of the bone is apt to slip out of place again owing to the pull of the biceps.

A general anesthetic is required for reduction, because it may be necessary to employ manipulations for a considerable time in order to get the remains of the orbicular ligament out of the lesser sigmoid cavity, and greater nicety of manipulation is required than is possible without its aid. The elbow is bent to a right angle and traction is made upon the

Inb

FIG. 21.-APPARATUS FOR USE AFTER DISLOCATION OF THE HEAD OF THE RADIUS FORWARDS. The posterior rectangular splint is of wood; the anterior splint is a moulded one, and has a pad between it and the front of the head of the radius.

forearm, whilst the head of the radius is pressed backwards into position with the thumb of the hand that fixes the arm. It is easy to get the head of the bone nearly into place, but the reduction is not satisfactory unless the bone remains in position with the aid of very slight pressure from the thumb, and pronation and supination are free. If the divided ends of the orbicular ligament curl up between the head of the radius and the ulna, these movements will be hampered, and the head of the bone will betray a constant tendency to slip out of position, particularly when full pronation is performed.

After-treatment. When reduction is complete, the elbow is put up upon a

posterior rectangular splint with the forearm fully supinated; a moulded anterior splint of guttapercha or poroplastic material with a pad between it and the front of the head of the radius should be employed to press the latter back (see Fig. 21).

It is important to practise pronation and supination daily within a week from the time of the accident, as otherwise troublesome adhesions may form. The movements should always be carried out by the surgeon himself, and displacement of the head of the radius should be guarded against by applying pressure over it by the thumb. The splint and pad should be kept on for the first three weeks; after that time the patient may discard the splint, but should keep the arm in a sling for another two

weeks. The patient should not carry heavy weights or attempt any forcible movements for at least another fortnight.

Operative measures.—If it is evident that reduction is not satisfactory, it will be necessary to expose the articulation and remove the remains of the orbicular ligament; otherwise the dislocation will recur and will lead to disability which may require for its cure an operation under less favourable circumstances.

The head of the radius is readily exposed by the angular incision recommended by Kocher for

excision of the elbow. The joint is flexed to an angle of 150°, and an incision is commenced one inch above the external condyle and carried down along the external supracondyloid ridge to the head of the radius, and thence to the subcutaneous border of the ulna three inches below the tip of the olecranon (see Fig. 22). This incision runs between the supinator longus and the triceps above, and between the extensor carpi ulnaris and the anconeus below, and exposes the radio-humeral joint without damaging any important

structure.

The capsule of the joint is now incised at its posterior aspect, and the head of the radius will then be seen. The orbicular ligament is defined and the torn ends held aside, after which it is easy to press the head of the bone into position. The torn ends of the orbicular ligament are then stitched together if possible, but, should the ligament be torn close to its insertion into the ulna, it may be very difficult to repair the injury; as a rule, however, the difficulty may be overcome by passing two or three catgut sutures through the end of the torn ligament, and then through the periosteum or the insertion of the ligament close to the bone, before the dislocation is reduced. These stitches are left loose and are tied when the head of the radius has been brought into position. The wound is closed without a drainage-tube. The after-treatment is similar to that for dislocation reduced by manipulation.

FIG. 22.-INCISION TO EXPOSE THE HEAD OF THE RADIUS. The deep fascia and the capsule of the joint have been incised directly over the head of the bone.

Dislocation of the head of the radius backwards or outwards is very rare, and the treatment resembles that of the form just described.

UNREDUCED DISLOCATION.-The trouble in these cases. is that flexion cannot be carried out even up to a right angle, whilst the movements of pronation and supination are interfered with.

Treatment. When the dislocation is of long-standing, it is obviously impossible to obtain satisfactory reduction by mere manipulation, as the alterations in the radio-ulnar joint entirely preclude this. We have, however, obtained satisfactory results by cutting down upon the articulation in the manner just described, and removing the head of the bone (see p. 43). The sigmoid cavity is then cleared of fibrous tissue, and the upper end of the bone is pressed back into position. If enough bone be removed to enable full flexion to be carried out, the result is satisfactory. It is well to introduce some soft tissues between the upper end of the radius and the humerus and ulna so as to prevent bony union between the radius and the ulna (see p. 153). A flap of fascia may be obtained from the outer side of the upper part of the forearm, the base of the flap being over the ulna.

The wound is sewn up without a drainage-tube, and no splint is employed; a mass of dressing is put on to immobilise the joint, and the arm is carried in a sling. The passive movements of pronation and supination are practised from the day following the operation, and as soon as the wound has healed, the patient is encouraged to move the arm.

'PULLED ARM.'-Before leaving the question of dislocation of the head of the radius, it is necessary to refer to those cases, so frequently met with in children, in which severe pain is felt in the neighbourhood of the superior radio-ulnar articulation accompanied by loss of pronation and supination, as the result of lifting the child up suddenly or swinging him round by the forearms. The child screams on any attempt to rotate the radius and the limb is powerless, and in a position midway between pronation and supination. Several explanations of this condition are put forward, the most probable being that the head of the radius has been partially withdrawn from the orbicular ligament, and that, as a result, folds of the synovial membrane covering the ligament lie over the head of the radius and are nipped between it and the articular surface of the humerus.

Treatment. That this explanation is the most probable one seems proved by the fact that the condition is easily remedied under anæsthesia by fixing the elbow-joint, firmly grasping the wrist, and then suddenly pronating and supinating the arm fully, if necessary deflecting the whole of the forearm somewhat outwards. As a rule the head of the bone slips into position at once, and the movements of the joint become free and painless.

CHAPTER V.

DISLOCATIONS OF THE WRIST AND FINGERS.

DISLOCATIONS OF THE WRIST.

DISLOCATION of the carpus from the radio-ulnar arch is of rare occurrence, and usually results from heavy falls or violent blows upon the outstretched palm, the hand being bent backwards and the wrist-joint over-extended. The displacement may be either forwards or backwards, the latter being the more common form. The condition is difficult to diagnose from Colles's fracture, with which it is often confounded; the points of diagnostic importance are the maintenance of the normal relative positions of the styloid processes and the absence of any displacement of the hand to the radial side in dislocation.

TREATMENT.-This can be carried out without an anesthetic. The dislocation is readily reduced by traction, which brings the articular surfaces into contact, and there is little tendency to recurrence of the deformity. It is well to lay the hand upon an anterior splint for a few days and to employ the ordinary evaporating lotions (see Vol. I. p. 9), as there is often considerable effusion into the joint and the tendon sheaths around it. Massage should be practised from the first.

The splint may be left off in a week and the arm kept in a sling for two or three weeks longer, whilst massage and passive movement are persevered with. The result is usually satisfactory.

DISLOCATIONS OF THE CARPAL BONES.

Dislocation of one carpal bone from another, is not nearly so rare as was at one time supposed; it usually occurs in connection with crushes of the hand or run-over injuries. Some sprains' of the wrist are examples of this injury, and it is always advisable in doubtful cases to obtain a stereoscopic radiogram of the joint. In most cases it is best to remove the displaced bone. We have had a considerable number of