Chapter 11

INJURIES IN THE REGION OF THE WRIST AND HAND

Surgical Anatomy--FRACTURE OF LOWER END OF RADIUS: _Colles' fracture_; _Chauffeur's fracture_; _Smith's fracture_; _Longitudinal fracture_; _Separation of epiphysis_--FRACTURE OF LOWER END OF ULNA: _Shaft_; _Styloid process_; _Separation of epiphysis_--FRACTURE OF CARPAL BONES--DISLOCATION: _Inferior radio-ulnar joint_; _Radio-carpal joint_; _Carpal bones_; _Carpo-metacarpal joint_--SPRAINS--INJURIES OF FINGERS: _Fractures_; _Dislocations_; _Mallet finger_.

INJURIES IN THE REGION OF THE WRIST

These include fractures of the lower ends of the bones of the forearm and separation of their epiphyses; sprains and dislocations of the inferior radio-ulnar, and of the radio-carpal articulations; and fractures and dislocations of the carpus.

#Surgical Anatomy.#--The most important landmarks in the region of the wrist are the styloid processes of the radius and ulna. The tip of the radial styloid is palpable in the "anatomical snuff-box" between the tendons of the long and short extensors of the thumb, and it lies about half an inch lower than the ulnar styloid. The ulnar styloid is best recognised on making deep pressure a little below and in front of the head of the ulna, which forms the rounded subcutaneous prominence seen on the back of the wrist when the hand is pronated.

The tubercle of the navicular (scaphoid) and the greater multangular (trapezium) can be felt between the radial styloid and the ball of the thumb, a little below the radial styloid; and the pisiform and hook of the hamatum (unciform) are palpable, slightly below and in front of the ulnar styloid.

In examining an injured wrist, the different bony points should be located, and their relative positions to one another and to the adjacent joints noted; and the shape, position, and relations of any unnatural projection or depression observed, using the wrist on the other side as the normal standard for comparison. The power and range of movement--active and passive--at the various joints should also be tested.

FRACTURE OF THE LOWER END OF THE RADIUS

#Colles' Fracture.#--This injury, which was described by Colles of Dublin in 1814, is one of the commonest fractures in the body, and is especially frequent in women beyond middle age. It is almost invariably the result of a fall on the palm of the hand, in the three-quarters pronated position, the force being received on the ball of the thumb, and transmitted through the carpus to the lower end of the radius which is broken off, the lower fragment being driven backwards.

The fracture takes place through the cancellated extremity of the bone, within a half to three-quarters of an inch of its articular surface (Fig. 45). It is usually transverse, but may be slightly oblique from above downwards and from the radial to the ulnar side. In a considerable proportion of cases it is impacted, and not infrequently the lower fragment is comminuted, the fracture extending into the radio-carpal joint.

When impaction takes place, it is usually reciprocal, the dorsal edge of the proximal fragment piercing the distal fragment, and the palmar edge of the distal fragment piercing the proximal. The periosteum is usually torn and stripped from the palmar aspect of the fragments, while it remains intact on the dorsum.

In the majority of cases the styloid process of the ulna is torn off by traction exerted through the medial ulno-carpal (internal lateral) ligament, and in a considerable proportion there is also a fracture of one of the carpal bones.

The resulting _displacement_ is of a threefold character: (1) the distal fragment is displaced backwards; (2) its carpal surface is rotated backwards on a transverse diameter of the forearm; while (3) the whole fragment is rotated so that the radial styloid comes to lie at a higher level than normal.

_Clinical Features._--In a typical case there is a prominence on the dorsum of the wrist, caused by the displaced distal fragment, with a depression just above it (Fig. 43); and the wrist is broadened from side to side. The natural hollow on the palmar aspect of the radius is filled up by the projection of the proximal fragment. The carpus is carried to the radial side by the upward rotation of the distal fragment, and the radial styloid is as high, or even higher, than that of the ulna. The lower end of the ulna is rendered unduly prominent by the flexion of the hand to the radial side. The fingers are partly flexed and slightly deviated towards the ulnar side; and the patient supports the injured wrist in the palm of the opposite hand, and avoids movement of the part. Occasionally the median nerve is bruised or torn, causing motor and sensory disturbances in its area of distribution.

The general outline of the wrist and hand has been compared not inaptly to that of "an inverted spoon." Pronation and stipulation are lost, the joint is swollen, and there is tenderness on pressure, especially over the line of fracture. Tenderness over the position of the ulnar styloid may indicate fracture of that process, although it is sometimes present without fracture. No attempt should be made to elicit crepitus in a suspected case of Colles' fracture as the manipulations are painful, and are liable to increase the displacement.

_Treatment._--It cannot be too strongly insisted upon that success in the treatment of Colles' fracture with displacement and impaction depends chiefly upon complete and accurate reduction, and to enable this to be effected a general anaesthetic is almost essential. The surgeon grasps the patient's hand, as if shaking hands with him, and, resting the palmar surface of the wrist on his bent knee, makes traction through the hand, and counter-extension through the forearm, with lateral movements, if necessary, to undo impaction. When the fragments are freed from one another, the wrist is flexed, and the hand carried to the ulnar side, while the lower fragment is moulded into position by the thumb of the surgeon's disengaged hand. When reduction is complete, the deformity disappears, and the two styloid processes regain their normal positions relative to one another.

As there is no tendency to re-displacement and no risk of non-union, no retentive apparatus is required, but, if it adds to the patient's sense of security, a bandage or a poroplastic wristlet may be applied. In severe cases, however, anterior and posterior splints, similar to those used for fracture of both bones of the forearm, or a dorsal splint padded so as to flex the wrist to an angle of 45 deg., but somewhat narrower, may be employed. The hand and forearm are in any case supported in a sling.

To avoid the stiffness that is liable to follow, massage and movement of the wrist and fingers should be carried out from the first, the range of movement being gradually increased until the function of the joints is perfectly restored. If splints are used, they should be discarded in a week, and the patient is then encouraged to use the wrist freely.

The various special splints recommended for the treatment of Colles' fracture, such as Carr's, Gordon's, the "pistol splint," and many others, are all designed to correct the deformity as well as to control the fragments. It has already been pointed out that if reduction is complete there is no deformity to correct, and if it is not complete the deformity cannot be corrected by any form of splint.

_Unreduced Colles' Fracture._--When union has been allowed to take place without the displacement having been reduced, an unsightly deformity results. In young subjects whose occupation is likely to be interfered with, and in women for aesthetic reasons, the fracture is reproduced and the displacement of the lower fragment corrected. This is conveniently done by means of Jones' wrench, which grasps the distal fragment and affords sufficient leverage to break the bone.

#Chauffeur's Fracture.#--A fracture of the lower end of the radius frequently occurs from the recoil of the crank, "by back firing," in starting the engine of a motor-car. The injury may be produced either by direct violence, the handle as it recoils striking the forearm, or by indirect violence, from forcible hyper-extension of the hand while grasping the handle. The fracture may pass transversely through the lower end of the radius, as in Colles' fracture, but is more often met with two or three inches above the wrist (Fig. 46). It is treated on the same lines as Colles' fracture.

A fracture of the lower end of the radius _with forward displacement of the carpal fragment_, was first described by R. W. Smith of Dublin (_Colles' fracture reversed_, or #Smith's fracture#) (Fig. 47). It is nearly always due to forcible flexion, as from a fall on the back of the hand. Like Colles' fracture, it may be transverse or slightly oblique, impacted, or comminuted. The deformity is characterised by an elevation on the dorsum running obliquely upwards from the ulnar to the radial side of the wrist, and caused by the head of the ulna, which remains in position, and the distal end of the proximal fragment. Below this, over the position of the distal radial fragment, is a gradual slope downwards on to the dorsum of the hand. Anteriorly there is a prominence in the flexure of the wrist, and the distal fragment may be felt under the flexor tendons. The hand deviates to the radial side, and thereby still further increases the prominence caused by the lower end of the ulna. The radial styloid is displaced forward, upward, and to the radial side, and the ulnar styloid may be torn off.

When the deformity is not well marked, this injury may be mistaken for forward dislocation of the wrist, for fracture of both bones low down, or for sprain of the joint.

The _treatment_ is carried out on the same lines as in Colles' fracture.

_Longitudinal fractures_ of the lower end of the radius opening into the joint usually result from the hand being crushed by a heavy weight or in machinery. They are often compound and comminuted.

#Separation of the lower epiphysis# of the radius, which is on the same level as that of the ulna and lies above the level of the synovial membrane of the wrist-joint, is comparatively common between the ages of seven and eighteen, especially in boys, and is caused by the same forms of violence as produce Colles' fracture.

Although clinically the appearances in these two injuries bear a general resemblance to one another, separation of the epiphysis may usually be identified by the directly transverse line of the dorsal and palmar projections, the folding of the skin observed in the palmar depression, the absence of abduction of the hand and the ease with which muffled crepitus can be elicited (E. H. Bennett). The deformity is readily reduced, and the fragments are easily retained in position.

This injury is often complicated with fracture of the shaft or styloid process of the ulna, or with dislocation of the radio-ulnar joint, and it is not infrequently compound, the lower end of the shaft being driven through the skin on the palmar aspect immediately above the wrist. Impairment of growth in the radius seldom occurs; when it does, it results in a valgus condition of the hand (Fig. 48), calling for resection of the lower end of the ulna.

The _treatment_ is the same as for Colles' fracture.

#Fracture of the Lower End of the Ulna.#--The lower end of the _shaft_ of the ulna is seldom fractured alone. The _styloid process_, as has already been pointed out, is frequently broken in association with Colles' and other fractures of the lower end of the radius.

Separation of the _lower epiphysis_ of the ulna sometimes occurs, and in rare cases results in arrest of the growth of the bone, leading to a varus condition of the hand and bending of the radius. Sometimes the separated epiphysis fails to unite, and although this gives rise to no disability, it is liable to lead to errors in the interpretation of skiagrams.

The _treatment_ is similar to that for the corresponding injuries of the radius.

Simultaneous separation of the _epiphysis of both radius and ulna_ sometimes occurs, and, as a result of severe violence, may be compound, the lower ends of the diaphyses projecting through the skin on the palmar aspect above the wrist.

#Fracture of Carpal Bones.#--The use of the Roentgen rays has shown that fracture of individual carpal bones is commoner than was previously supposed, and that many cases formerly looked upon as severe sprains are examples of this injury.

The _navicular_ (scaphoid) and _lunate_ (semilunar) are those most commonly fractured, usually by indirect violence, by forced dorsiflexion from a fall on the extended hand. The clinical features are: localised swelling on the radial side of the wrist, increase in the antero-posterior diameter of the carpus, marked tenderness in the anatomical snuff-box when the hand is moved laterally, especially in the direction of adduction, and, rarely, crepitus. The median nerve is sometimes over-stretched or partly torn. In many cases, however, the symptoms are so obscure that an accurate diagnosis can only be made by the use of the X-rays (Fig. 49). Codman recommends taking pictures of the navicular by placing the two wrists of the patient in adduction, and of the lunate, in abduction.

The _treatment_ of simple fractures consists in massage and movement. Codman and Chase recommend excision of the proximal half of the fractured bone, through a dorsal incision to the lateral side of the extensor digitorum communis. When the fracture is compound, the loose fragments should be removed.

DISLOCATIONS IN THE REGION OF THE WRIST

Dislocation may occur at the inferior radio-ulnar, the radio-carpal, mid-carpal, inter-carpal, or carpo-metacarpal joints, but the strong ligaments of these articulations, the comparatively free movement at the various joints, and the relative weakness of the lower end of the radius whereby it is so frequently fractured, render dislocation a rare form of injury.

Dislocation of the #inferior radio-ulnar# articulation may complicate fracture of the lower end of the radius, or accompany sub-luxation of the head of the radius. The head of the ulna usually passes backward.

In children, the commonest cause is lifting the child by the hand, and the displacement is only partial. In adults, it may result from forcible efforts at pronation or supination, as in wringing clothes, or from direct violence, the separation being frequently complete, and sometimes compound.

The head of the ulna is unduly prominent, and there is a depression on the opposite aspect of the joint. The hand is generally pronated, the rotatory movements at the wrist are restricted and painful, while flexion and extension are comparatively free.

Reduction is effected by making pressure on the displaced bone and manipulating the joint, especially in the direction of supination. If the ligaments fail to unite, the head of the ulna tends to slip out of place in pronation and supination--_recurrent dislocation_.

Dislocation at the #radio-carpal# articulation, usually spoken of as _dislocation of the wrist_, is attended by tearing of the ligaments and displacement of tendons, and is frequently compound. The carpus may be displaced backward or forward, and the articular edge of the radius towards which it passes may be chipped off.

_Backward_ dislocation is commonest, the injury resulting from a severe form of violence, such as a fall from a height on the palm while the hand is dorsiflexed and abducted. The clinical appearances closely simulate those of Colles' fracture, or of separation of the lower radial epiphysis, but the unnatural projections, both in front and behind, are lower down, and end more abruptly (Fig. 50). The hand is more flexed, and the palm is shortened. The styloid processes retain their normal relations to one another, and the carpal bones lie on a plane posterior to the styloids, the articular surfaces may be recognised on palpation. The forearm is not shortened.

_Forward_ dislocation of the carpus may result from any form of forced flexion, such as a fall on the back of the hand, or from direct violence. The displaced carpus forms a marked projection on the palmar aspect of the wrist, and there is a corresponding depression on the dorsum. The attitude of the hand and fingers is usually one of flexion.

In both varieties reduction is readily effected by making traction on the hand and pushing the carpus into position. A moulded poroplastic splint, which keeps the hand slightly dorsiflexed, adds to the comfort of the patient, but this should be removed daily to admit of movement and massage being employed.

#Dislocation of Carpal Bones.#--The two rows of carpal bones may be separated from one another, or any one of the individual bones may be displaced. These injuries are rare, and result from severe forms of violence, usually from a fall on the extended hand. Pain, deformity, and loss of function are the ordinary symptoms. The treatment consists in making direct pressure over the displaced bone, while traction is made on the hand, which is alternately flexed and extended.

Of these injuries that most frequently observed is displacement of the _head of the capitate bone_ (_os magnum_) from the navicular (scaphoid) and lunate (semilunar) bones. Frequently these bones are fractured, and fragments accompany the displaced os magnum. In full palmar flexion of the wrist the displaced head of the os magnum forms a prominence on the dorsum opposite the base of the third metacarpal, which temporarily disappears when the hand is dorsiflexed. There is an increase in the antero-posterior diameter of the wrist, situated on a lower level than that which accompanies fracture of the lower end of the radius; flexion and extension of the wrist are limited; and in some cases there are symptoms referable to pressure on the median nerve. By keeping the hand in the dorsiflexed position for a week or ten days, the bone may become fixed in its place and the function of the wrist be restored, but it is often necessary to excise the bone.

The _lunate_ may be displaced forward by forcible dorsiflexion of the hand, and forms a projection beneath the flexor tendons; there is usually loss of sensibility in the distribution of the ulnar nerve in the hand. The most satisfactory treatment is removal of the bone.

In a few cases the _navicular_ has been displaced (Fig. 51), and has had to be subsequently replaced by operation. Separation of any of the other bones is rare.

#Carpo-metacarpal Dislocations.#--Any or all of the metacarpal bones may be separated from the carpus by forced movements of flexion or extension. The commonest displacement is backward. The thumb seems to suffer oftener than the other digits. These injuries, however, are so rare, and the deformity is so characteristic, that a detailed description is unnecessary.

#Sprain of the wrist# is a common injury, and results from a fall on the hand, a twist of the wrist, or from the back-firing of a motor-crank dorsiflexing the hand. The marked swelling which rapidly ensues may render it difficult to distinguish a sprain from the other injuries that are liable to result from similar causes--Colles' fracture, separation of the lower radial epiphysis, dislocation of the wrist, and fractures and dislocations of the carpal bones.

In a sprain the normal relations of the styloid processes and other bony points about the wrist are unaltered, and there is no radial deviation of the hand, as in Colles' fracture. The most marked swelling is over the line of the articulation on the anterior and posterior aspects of the joint. There is usually some effusion into the sheaths of the tendons passing over the joint, and in some cases on moving the fingers a peculiar creaking, which may simulate crepitus, can be elicited. There is marked tenderness on making pressure over the line of the joint, as well as over one or other of the collateral ligaments, depending upon which ligament has been over-stretched or torn. Movements that tend to put the damaged ligaments on the stretch also cause pain. It has to be borne in mind, however, that in many cases of Colles' fracture there is extreme tenderness on pressing over the ulnar styloid and medial ulno-carpal ligament, as these structures are frequently injured as well as the radius, but the point of maximum pain and tenderness is over the seat of fracture of the radius. In all doubtful cases the X-rays should be employed to establish the diagnosis.

The _treatment_ consists in the immediate employment of massage and movement, supplemented by alternate hot and cold douches, on the same lines as in sprains of other joints.

INJURIES OF THE FINGERS

#Fracture.#--_Fractures of the metacarpals of the fingers_ are comparatively common. When they result from direct violence, such as a crush between two heavy objects, they are often multiple and compound. Indirect violence, acting in the long axis of the bone and increasing its natural curve, such as a blow on the knuckle in striking with the closed fist, usually produces an oblique fracture about the middle of the shaft, the proximal end of the distal fragment projecting towards the dorsum. Apart from this there is little deformity, as the adjacent metacarpals act as natural splints and tend to retain the fragments in position. A sudden sharp pain may be elicited at the seat of fracture on making pressure in the long axis of the finger; and unnatural mobility and crepitus may usually be detected. These fractures are readily recognised by the X-rays. Firm union usually results in three weeks.

The shaft of the _metacarpal of the thumb_ is frequently broken by a blow with the closed fist. The fracture is usually transverse, and situated near the proximal end of the shaft; frequently it is comminuted, and in some instances there is a longitudinal split.

_Treatment._--When the fracture is transverse, and especially when it implicates the middle or ring fingers, the most convenient method is to make the patient grasp a firm pad, such as a roller bandage covered with a layer of wool, and to fix the closed fist by a figure-of-eight bandage. In this way the adjoining metacarpals are utilised as side splints. Active and passive movements must be carried out from the first, and the bandage may be dispensed with at the end of a week or ten days.

In oblique fractures with a tendency to overriding of the fragments, especially in the case of the index and little fingers, it is sometimes necessary to apply extension to the distal segment of the digit, by means of adhesive plaster, to which elastic tubing is attached and fixed to the end of a bow splint, reaching well beyond the finger-tips (Fig. 52). This should be worn for a week or ten days.

#Bennett's Fracture of the Base of the First Metacarpal Bone.#--Bennett of Dublin described an injury of the thumb which, although comparatively common, is often mistaken for a sub-luxation backward of the carpo-metacarpal joint, or a simple "stave of the thumb." It consists in an "oblique fracture through the base of the bone, detaching the greater part of the articular facet with that piece of the bone supporting it which projects into the palm" (Fig. 53). We have frequently observed the fracture extend for a considerable distance along the palmar aspect of the shaft.

It usually results from severe force applied directly to the point of the thumb, driving the metacarpal against the greater multangular bone (trapezium), and chipping off the palmar part of the articular surface, but it may result from a blow with the closed fist. The rest of the metacarpal slips backward, forming a prominence on the dorsal aspect of the joint. The pain and swelling in the region of the fracture often prevent crepitus being elicited, and as the deformity is not at once evident, the nature of the injury is liable to be overlooked. The fracture is recognised by the use of the X-rays. Unless properly treated this injury may result in prolonged impairment of function, full abduction and fine movements requiring close apposition of the thumb being specially interfered with.

The _treatment_ consists in reducing the fracture by extension in the attitude of full abduction and applying an accurately fitting pad over the extremity of the displaced bone, maintained in position by a light angular splint. This splint is first fixed to the extended and abducted thumb, and while extension is made by pushing it downwards the upper end is fixed to the wrist (Fig. 54 A). The apparatus is worn for three weeks, being carefully readjusted from time to time to maintain the extension and abduction. A moulded poroplastic splint added on the same principle may be employed, and is more comfortable (Fig. 54 B). Excellent results are obtained after reduction of the displacement, by massage and movement from the first, and the support merely of a figure-of-eight bandage (Pirie Watson).

#Fractures of phalanges# usually result from direct violence, and on account of the superficial position of the bones, are often compound, and attended with much bruising of soft parts. Force applied to the distal end of the finger may also fracture a phalanx. The proximal phalanges are broken oftener than the others. The deformity is usually angular, with the apex towards the palm, and if union takes place in this position, the power of grasping is interfered with. Unnatural mobility and crepitus can usually be recognised, but, on account of the swelling and tenderness, the fracture is apt to be overlooked. Firm union takes place in two or three weeks. In oblique and comminuted fractures, union may take place with overlapping, producing a deformity which may prevent the wearing of a glove or of rings. In compound fractures, non-union sometimes occurs, and causes persistent disability. In doubtful cases radioscopy renders valuable aid, as the parts are readily seen with the screen.

_Treatment._--Early movement and massage are all-important. The contiguous fingers may be utilised as side splints, and a long palmar splint projecting beyond the fingers is applied. In oblique and comminuted fractures it may be necessary to anaesthetise the patient to effect reduction. When it is particularly desirable to avoid deformity, an open operation may be advisable.

#Dislocation.#--_Dislocation of the Metacarpo-phalangeal Joint of the Thumb._--The commonest dislocation at this joint is a _backward_ displacement of the proximal phalanx, which may be complete or incomplete. Its special clinical importance lies in the fact that much difficulty is often experienced in effecting reduction.

This dislocation is usually produced by extreme dorsiflexion of the thumb, whereby the volar accessory (palmar) and the collateral ligaments are torn from their metacarpal attachments, the phalanx carrying with it the volar accessory ligament and sesamoid bones. The head of the metacarpal passes forward between the two heads of the short flexor of the thumb, and the tendon of the long flexor slips to the ulnar side. The phalanx passes on to the dorsum of the metacarpal, where it is held erect by the tension of the abductor and adductor muscles.

The attitude of the thumb is characteristic. The metacarpal is adducted, its head forming a marked prominence on the front of the thenar eminence, and the phalanges are displaced backwards, the proximal being dorsiflexed and the distal flexed towards the palm.

Many explanations of the difficulty so often experienced in reducing this variety of dislocation have been offered, but the consensus of opinion seems to be that it is due to the interposition of the volar accessory ligament and the sesamoid bones between the phalanx and the metacarpal, and that this is most frequently the result of ill-advised efforts at reduction. In some cases the tension of the long flexor tendon may be a factor in preventing reduction, but the "button-holing" by the short flexor is probably of no importance.

Reduction is to be effected by flexing and abducting the metacarpal while the phalanx is hyper-extended and pushed down towards the joint and levered over the head of the metacarpal.

When this manipulation fails, the volar accessory ligament should be divided longitudinally through a puncture made with a tenotomy knife on the dorsal aspect of the joint, so as to separate the sesamoid bones and permit the passage of the head between them. An open operation is seldom necessary.

Dislocation _forward_ is rare. It results from forced flexion of the thumb with abduction, tearing the posterior and medial collateral ligaments. The deformity is characteristic: the rounded head of the metacarpal projecting behind the level of the joint, while the base of the phalanx forms a prominence among the muscles of the thenar eminence.

Reduction is easily effected by making traction on the phalanges and carrying out movements of flexion and extension. The deformity, however, is liable to be reproduced unless a retentive apparatus is securely applied.

Dislocation of the thumb to one or other side is rare.

Dislocations of the _metacarpo-phalangeal joint of the fingers_ may be backward or forward. They are less common than those of the thumb, but present the same general characters. In the backward variety the same difficulty in reduction occurs as is met with in the corresponding dislocation of the thumb, and is to be dealt with on the same lines.

_Inter-phalangeal Dislocation._--The second and the ungual phalanges may be displaced backwards, forwards, or to the side. The clinical features are characteristic, and the diagnosis, as well as reduction, is easy. These dislocations are frequently the result of machinery accidents, and being compound and difficult to render aseptic, often necessitate amputation.

_Persistent flexion of the terminal phalanx_ of the thumb or fingers (_drop_ or _mallet finger_) may result from violence applied to the end of the digit when in the extended position--as, for example, in attempting to catch a cricket-ball. The terminal phalanx is flexed towards the palm, and the patient is unable to extend it voluntarily. A palmar splint is applied securing extension of the distal joint for three or four weeks. If the deformity has been allowed to occur it can only be corrected by an open operation, suturing or tightening the extensor tendon at its insertion into the base of the terminal phalanx.