Chapter 17

DEFORMITIES OF THE EXTREMITIES

The origin of deformities: (1) Those arising before birth; (2) those produced during birth; and (3) those acquired after birth.

Palsies of children: _Anterior Poliomyelitis_. Cerebral palsies: _Spastic paralysis_.

THE LOWER EXTREMITY: Congenital dislocation of hip--Snapping hip--Paralytic deformities--Contracture and ankylosis of hip--Coxa vara and coxa valga--Congenital dislocation of knee and patella--Genu recurvatum--Paralytic deformities--Contracture and ankylosis of knee--Genu valgum and genu varum--Congenital deformities of leg--Bow-leg--Club-foot: _Talipes equino-varus_; _Pes equinus_; _Pes calcaneus_; _Pes calcaneo-valgus and varus_; _Pes cavus_; Flat-foot and pes valgus--Painful affections of heel--Metatarsalgia--Hallux valgus and bunion--Hallux varus--Hallux rigidus and flexus--Hammer-toe--Hypertrophy of toes--Supernumerary toes--Webbed toes.

THE UPPER EXTREMITY: Congenital absence of clavicle--Elevation of scapula--Winged scapula--Congenital paralytic deformities of shoulder--Deformities of elbow--Club-hand--Deformities of wrist--Madelung's deformity--Deformities of fingers--Dupuytren's contraction--Polydactylism.

The surgery of the extremities is so largely concerned with the correction of deformities that it is necessary at the outset to refer briefly to some points relating to the time and mode of origin of these.

1. _Congenital deformities_--that is, those which originate _in utero_ and are present at birth--are comparatively common and may be due to a variety of causes. Some result from errors of development--for example, supernumerary fingers or toes, and deficiencies in the bones of the leg or forearm. A larger number are to be attributed to a persistent abnormal attitude of the foetus, usually associated with want of room in the uterus--for example, the common form of club-foot and congenital dislocation of the hip. Less frequently amniotic bands so constrict the digits or the limbs as to produce distortion, or even to sever the distal part--_intra-uterine amputation_. Lastly, certain diseases of the foetus, and particularly such as affect the skeleton--for example, achondroplasia--cause congenital deformities.

2. _Deformities originating during birth_ are all traceable to the effects of injuries sustained in the course of a difficult labour. Examples of these are: wry-neck resulting from rupture of the sterno-mastoid; lesions of the shoulder-joint and brachial plexus due to hyper-extension of the arm; a spastic condition of the lower limbs--Little's disease--resulting from tearing of blood vessels on the surface of the brain with haemorrhage and interference with the function of the cortical motor area.

3. _Deformities acquired after birth_ arise from widely different causes, of which diseases of bone, including rickets, diseases of joints, and affections of the nervous system attended with paralysis, are amongst the commonest. Other deformities are produced by unsuitable clothing, such as a tight corset, or ill-fitting shoes distorting the toes, prolonged standing in growing subjects overstraining the mechanism of the foot and giving rise to the common form of flat-foot.

The part played by the palsies of children in the surgical affections of the extremities necessitates a short description of their more important features.

#Anterior poliomyelitis# is the lesion underlying what was formerly known as _infantile paralysis_--a name to be avoided, because the condition is not confined to infants and it is not the only form of paralysis met with in young children. Anterior poliomyelitis is characterised by an illness attended with fever, in which the child is found to have lost the power of one, less frequently of both lower extremities; or, it may be, of one or both arms. After a period, varying from six weeks to three months, the paralysis tends to diminish both in extent and degree, and in the majority of cases it ultimately persists only in certain muscles or groups of muscles. At the onset of the paralysis the affected limb is helpless and relaxed, the reflexes are lost, the muscles waste, and those that are paralysed exhibit the reaction of degeneration. In severe cases, and especially if proper treatment is neglected, the nutrition of the limb is profoundly affected; its temperature is subnormal, the skin is bluish in cold weather and readily becomes the seat of pressure sores. In course of time the limb lags behind its fellow in growth, and tends to assume a deformed attitude, which at first can easily be corrected, but later becomes permanent.

When the acute stage of the illness is past, the chief question is to what extent recovery of function can be looked for in the paralysed muscles.

It would appear to be established that if a muscle reacts to faradism it will recover, but the contrary proposition does not follow. It was formerly accepted that a muscle which exhibits the reaction of degeneration is incapable of recovery, but observation has shown that this is not the case. Complete destruction of the motor cells in the anterior horn of grey matter as a result of poliomyelitis is now known to be exceptional; as a matter of fact, damage to the nerve cells is usually capable of being repaired. The muscles governed by these cells may appear to be completely paralysed, but with appropriate treatment their functional activity can be restored. As functional disability is frequently due to the affected muscle being _over-stretched_, it is of the first importance, when the acute symptoms are on the wane, that every care should be taken to prevent the weak muscular groups being put upon the stretch, and the greatest attention should be paid to _the posture of the limb during convalescence_. For example, if the child is allowed to lie with the wrist flexed, the flexor muscles undergo shortening, and the extensors are over-stretched and are therefore placed at a mechanical disadvantage. As the inflammatory changes in the anterior horn of the cord subside, the flexor tendons, from their position of advantage, are in a condition to respond to the first stimuli that come from their recovering motor cells, while the extensors are not in a position to do so. If, on the other hand, the wrist and fingers are maintained in the attitude of extreme dorsiflexion, the extensors become shortened, and, relieved of strain, they soon begin to respond to the stimuli sent them from the recovering nerve cells. Similarly in the lower extremity, when, for example, the muscles innervated through the peroneal (external popliteal) nerve are paralysed, if the foot is allowed to remain in the attitude of inversion with the heel drawn up--paralytic equino-varus--an attitude which is rendered more pronounced by the pressure of the bedclothes, the chance of the muscles recovering their function is seriously diminished. Another potent factor in preventing recovery, especially in the lower limbs, is _erroneous deflection of the body weight_. If, for example, there is weakness in the tibial group of muscles, and the child is allowed to walk, the eversion of the foot will steadily increase, the tibial muscles will be more and more stretched, the opposing peroneal muscles will shorten, and, in time, the bones of the tarsus will undergo structural alterations which will perpetuate the deformity. If, on the other hand, by some alteration of the boot, the foot is maintained in the attitude of inversion, the weakened or paralysed tibial muscles are placed in a much more favourable condition for recovery.

It must be emphasised that no operation should be performed in these cases until the question whether it be possible or not to restore the apparently paralysed muscle is settled. The clinical test of the recoverability of a muscle is to keep it for a long period--six or even twelve months--in a condition of relaxation. This test should be made, no matter how many months or years the muscle may have been paralysed.

The first stage in the treatment, therefore, is the correction of existing deformity, after which the limb should be kept immovable until the ligaments, muscles, and even the bones have regained their normal length and shape. The slightest stretching of a muscle which is in process of recovery disables it again.

The age of the patient influences the method of treatment. In young children in whom the structures are soft and yielding, gradual correction of the deformity is to be preferred to the more rapid methods employed in older children. The proper sequence consists in correcting the deformity, providing the simplest apparatus to keep the limb in good position, preventing erroneous deflection of body weight during walking, and then allowing the child to grow and develop until he has reached the age of five before considering such an operation as transplanting tendons, and the age of ten before deciding to ankylose a flail-like joint.

_Reposition, Manipulations, Supports._--An attempt is made to correct the deformity by manipulation, and the proper attitude is maintained by a mechanical support. If the foot has become rotated so that the sole looks laterally, the medial side of the boot must be raised, and an iron worn which extends from the knee down the lateral side of the leg, to end, without a joint, in the heel of the boot. In pes equinus, the iron is let into the back of the heel and extends forwards into the waist of the boot, to keep the foot at right angles to the leg and to relax the weak extensor muscles.

_Division of Contractions._--Bands of fascia and contracted tendons which prevent correction of deformity may have to be divided or lengthened. This is best done by the open method.

_Removal of Skin._--To assist in maintaining the desired attitude, Jones recommends the plan of excising an area of the redundant skin on the weaker aspect of the limb; in equinus, the skin is taken from the dorsum; in equino-varus, from the front and lateral aspect of the foot. When the edges of the gap have united, the foot is maintained in the desired attitude for some months, even if parents carelessly remove the iron support to let the child run about.

_Tendon transplantation_, a procedure introduced by Nicoladoni, is to be considered in children of five and upwards. It may be employed for different purposes: (1) To reinforce a weak muscle by a healthy one--for example, by transplanting a hamstring tendon into the patella to reinforce a weak quadriceps, or reinforcing the weak invertors of the foot by a transplanted extensor hallucis longus. (2) Transplantation may also be performed to replace a muscle which is quite inactive and does not show any sign of recovery--for example, the tibiales being paralysed, the peroneus longus may be implanted into the navicular or first metatarsal to act as an invertor of the foot.

Wherever possible a tendon should be transplanted directly into bone, as, if it is attached to soft parts it rarely holds firmly enough. The bone should if possible be tunnelled, and the tendon passed through the tunnel and securely fixed. When bringing a tendon to its new point of attachment, it should pass in as straight a line as possible, avoiding any bend or angle which might impair its action. Fat is the best medium for the transplanted tendon to traverse, as it acts as a sheath and prevents the formation of adhesions which would interfere with the function of the new tendon. All deformity must be corrected before transferring the tendon; if the tendon is too short to admit of this, it can be lengthened by means of silk threads (Lange).

According to Jones, the most successful transplantations are the following, in order: (1) The tibialis anterior into the lateral tarsus in paralysis of the peronei; (2) the peroneus longus into the navicular in paralysis of the tibial group; (3) the extensor hallucis longus into any part of the foot where it may be wanted; (4) the hamstrings into the patella, to reinforce the quadriceps, provided the strictest after-treatment can be secured; (5) deflection of part of the tendo Achillis to one or other side of the foot.

_Arthrodesis._--This operation, first performed by Albert in 1877, consists in removing the cartilage covering the articular surfaces of bones with the object of producing a firm ankylosis. The procedure is most successful in the ankle and mid-tarsal joints, and as a result of it there is obtained a secure and firm base of support in walking. Before performing arthrodesis, the surgeon must decide whether the patient will be better off with a stiff joint or with a weak and movable ankle supported by apparatus. This is often a matter of social position; in the poor, an ankylosed joint is more useful and less expensive. An arthrodesis should seldom be performed at the ankle until the child has passed his eighth year, or at the knee until he has reached his twentieth year. There is plenty to be done during the period of waiting, and if this is done well, it is possible that the operation may not be required. The existing deformities, for example, will have to be corrected, areas of skin removed to relieve functionless muscles of strain, the body weight appropriately deflected, and the child must be taught to walk with the aid of a support, swinging his limb about, and using it effectively in a correct position. Such exercise is a powerful agent in promoting physiological and functional development.

_Nerve anastomosis_, which seeks to provide a new channel for the transmission of motor impulses to the paralysed muscles, has as yet a restricted field of application--for example, the tibial and peroneal nerves may be anastomosed when the muscles supplied by one of them are paralysed. Stoffel of Heidelberg lays stress on regard being paid to the anatomical arrangement of the nerve bundles within the nerve-trunk so that motor fibres may be joined to motor ones and not to sensory. It is necessary also to cut across some of the fibres of the healthy nerve in order that they may grow into the nerve which is degenerated.

In extreme cases in which the limb is hopelessly paralysed and useless, it may be _amputated_ to admit of an artificial limb being worn; it must be borne in mind, however, that such limbs furnish poor stumps, usually quite unable to bear pressure.

#Cerebral Palsies of Childhood--Spastic Paralysis.#--These may be due to arrest of development of the brain, to injuries of the head at birth, to meningeal haemorrhage, or to other lesions of the brain, with secondary degenerative changes in the spinal cord. The commonest cause is haemorrhage occurring during child-birth from the veins which ascend from the middle part of the convexity of the hemisphere to open into the superior sagittal (superior longitudinal) sinus. The blood is poured out beneath the dura on one or on both sides of the falx cerebri, and as it accumulates near the vertex, the damage to the motor centres for the legs is usually more extensive than that to the centres for the arms. The paralysis may affect one side of the body--_hemiplegia_, or both sides--_diplegia_; less commonly one extremity alone is involved--_monoplegia_. In diplegia, in which both arms and both legs are affected in the first instance, the arms may recover while the lower extremities remain in a spastic state, a condition known as _Little's disease_. The mental functions may be normal but more frequently they are imperfectly developed, the impairment in some cases amounting to idiocy. The affected limbs exhibit muscular rigidity or spasm, which is aggravated on movement but disappears under an anaesthetic; the reflexes are exaggerated, and sometimes there are perverted involuntary movements (_athetosis_). The growth of the limb is impaired, and contracture deformities may supervene (Fig. 131). The amount of power in the limb is often astonishing, in marked contrast to what is observed to follow upon anterior poliomyelitis. The degree of natural improvement is by no means great, and normal function is almost never regained.

The _treatment_ is concerned in the first place with improving the condition of the muscles by methodical exercises and massage. When reflex irritability of the muscles with consequent spasm is a prominent feature, the reflex arc may be interrupted by _resection of the posterior nerve roots_ corresponding to the part affected. This operation, first suggested by Spiller but chiefly popularised by Foerster, has yielded the best results in cases of Little's disease, in which there still remains a considerable amount of voluntary movement, and yet there is inability to walk on account of involuntary spasm. In the case of the lower extremities, three or more of the lumbar and one or more of the sacral nerve roots are resected within the vertebral canal. Sensation is diminished but not abolished in the area of skin involved. Massage and exercises and, it may be, splints or apparatus are essential factors in promoting the recovery of function. It has not yet been decided whether the results of the resection of nerve roots justify the risk.

Apart from Foerster's operation, or when it has failed, the spasm of any individual muscle or group of muscles may be got rid of by diminishing the nerve supply to the muscle or by lengthening the tendon. Diminishing the nerve supply was suggested by Stoffel; it consists in exposing the motor nerve as it enters the muscle and resecting one-third or one-half of the fibres so as to reduce the innervation to the required degree. The method is still on its trial.

_Lengthening the Tendons._--In spastic paraplegia, for example, Jones resects the origins of the adductors longus and brevis, lengthens the tendo Achillis, divides the popliteal fascia and hamstrings, and transplants the biceps into the quadriceps; after which the limbs are put up in the attitude of wide abduction for six weeks. It is important that the patient should begin to walk with the legs wide apart and learn to balance himself without any feeling of insecurity; he should be taught to look at an object straight in front of him rather than on the ground.

THE LOWER EXTREMITY

CONGENITAL DISLOCATION OF THE HIP

This is the commonest of all congenital dislocations. Its frequency varies in different countries, being greater on the continent of Europe than in this country. It is more often unilateral than bilateral (about 4 to 1), and is about three times more common in girls than in boys.

The dislocation takes place in the early months of intra-uterine life, and may be associated with deficiency of the liquor amnii.

#Pathological Anatomy.#--_In the infant_, the anatomical changes in the joint are less marked than they are after the child has borne its weight on the limb. The acetabulum, never having been occupied by the head of the femur, is imperfectly developed; it remains flat and shallow, is partly filled with fibro-fatty tissue derived from the synovial membrane, and is always too small for the head of the femur. The cotyloid ligament being broader and thicker than usual, makes the osseous portion of the socket appear deeper than it really is. In unilateral cases the affected half of the pelvis is contracted, so that the pelvic basin is narrowed and oblique. The head of the femur is small, flattened, and, in some cases, conical; and the angle formed by the neck with the shaft is altered, sometimes diminished, it may be to a right angle--_coxa vara_ (Fig. 129); sometimes increased--_coxa valga_. There is also a variable degree of torsion of the neck, ante-torsion being of practical importance as it increases the difficulty of retaining the head in the socket. The capsule is lax and admits of the head passing upwards for a variable distance on to the dorsum ilii. In unilateral cases the ligamentum teres is elongated and thickened; in bilateral cases it is frequently absent.

In _children who have walked_, the head of the femur is pushed farther upwards on the dorsum ilii; the capsule becomes lengthened by supporting the weight of the body. That part of the capsule which arises from the lower margin of the acetabulum stretches across the socket and partly shuts it off from the rest of the joint cavity. In course of time the capsule becomes greatly thickened, and may present an hour-glass constriction about its middle, which may prove a serious obstacle to reduction. The socket becomes small and triangular, and there is almost no ledge against which the head of the femur can rest. A superficial depression may form on the ilium where it is pressed upon by the head of the femur, covered by the capsule; and in the course of years, as the head changes its position, several secondary sockets may be formed. No proper new bony socket forms like that in traumatic dislocations that remain unreduced because in the congenital variety the thickened capsule intervenes between the head of the bone and the dorsum ilii. The displacement of the head is most frequently backwards (dorsal luxation), and as the point of support thus falls behind the acetabulum the pelvis tilts forwards, and the lumbar spine becomes unduly concave (lordosis). The muscles of the hip and thigh alter in consequence of the changed relations; the gemelli, obturators, and piriformis are lengthened, the adductors, hamstrings, and ilio-psoas are shortened, while the glutei and quadriceps are but little altered. In rare cases the head is displaced upwards and lies immediately above the acetabulum.

_Clinical Features._--The condition rarely attracts attention until the child begins to walk, but sometimes the unusual breadth of the pelvis, the presence of a lump in the buttock, snapping about the hip, or a peculiar way of holding the limb, leads the parents to seek advice early. In _unilateral cases_, when the child has learned to walk at the late age of two, three, or it may even be four years, it is noticed that the back is hollow and the buttocks unduly prominent, and that there is a peculiar and characteristic limp; each time the weight of the body is put upon the affected limb, the trunk makes a sudden dip towards that side. There is no pain on walking. The affected limb is shortened, as is shown by the projection of the great trochanter above Nelaton's line; the shortening gradually increases, and in time may amount to several inches. It is partly compensated for by resting the affected limb on the balls of the toes and flexing the knee on the sound side. The gluteal fold is shorter, deeper, and higher than on the healthy side, and on account of the obliquity of the pelvis the spine shows a lateral curvature, with its concavity to the affected side. The movements at the hip-joint are free in all directions except abduction; on practising external rotation it is often found to be abnormally free; lastly, in young children, if the pelvis is fixed, the head of the bone may be made to glide up and down on the ilium.

_In bilateral cases_ the trunk appears well grown in contrast to the short lower limbs, the hollow of the back is exaggerated, the abdomen protrudes, the perineum is broadened, and the buttocks are unduly prominent. The gait is waddling like that of a duck, the trunk lurching from one side to the other with each step. In untreated cases the deformity and disability become more pronounced as the capsular and round ligaments are further stretched, the shortening and limp become more marked, the patient is easily fatigued by walking or standing, and is usually unfitted for earning a living. We have had under observation, however, an adult male with bilateral dislocation and extroversion of the bladder, who efficiently performed the duties of a carrier for many years.

Except in fat infants, the _diagnosis_ is not difficult; the absence of pain and tenderness, the freedom of motion and the absence of the head of the femur from its normal position, differentiate the condition from tuberculous disease of the joint, and from coxa vara and other deformities in the region of the hip. _Trendelenburg's test_ consists in noting the relative level of the buttocks when the patient stands on the affected leg. Normally the buttocks remain on the same level when the patient stands on one leg; in congenital dislocation the buttock of the limb raised from the ground drops to a lower level; in coxa vara it rises higher.

In paralytic conditions at the hip there may be considerable resemblance to dislocation, but the muscles are slack and wasted, and the normal attitude can easily be restored by pulling on the limb. The most certain means of diagnosis is by the X-rays, which show the position of the head of the bone in relation to the acetabulum, and any torsion of the neck of the femur that may be present. This last point is determined by taking a series of skiagrams in different positions of the limb; these are also useful in correcting erroneous impressions as to the angle of the neck of the femur.

_Treatment._--We are indebted to Paci, Schede, Calot, Lorenz, and Hoffa for the rational treatment which seeks to reduce the dislocation by manipulation.

#Reduction by Manipulation# (_Method of Lorenz_).--The child is anaesthetised and placed on its back with the legs over the end of the table. While an assistant steadies the pelvis, the surgeon pulls on the limb so as to bring the trochanter down to Nelaton's line; this is followed by forced rotation outwards and inwards and forcible abduction to a right angle, and by kneading the adductors till they are stretched and torn. The next step is to stretch the hamstrings, and this is done by raising the foot, without bending the knee, until the front of the thigh meets the abdomen, and the toes the face. To stretch the anterior muscles, the patient is turned on the side or face, and the hip is hyper-extended both in the straight and in the abducted position. The stage is now reached at which attempts at reduction may be made; the child is again laid on its back, the surgeon grasps the knee, flexes the thigh to a right angle, rotates laterally, and slowly flexes and abducts, while the thumb pushes from behind on the trochanter, trying to guide and lift it over the rim of the socket as the hip reaches the over-abducted position. Lorenz uses a wedge of wood padded with leather about 3 inches high to rest the trochanter upon while attempting to lift it forward. When reduction takes place, there is generally a sound and a sudden jump, as in reducing a traumatic dislocation.

To keep the head in the socket, the limb must be maintained in the position of right-angled abduction and external rotation (90 deg.) by a plaster case, which includes the lower part of the trunk and both limbs down to the knee. Under the plaster, stockinette drawers are worn, and the bony prominences are padded with cotton wool. The plaster should overlap the costal margin. The first case is worn for two months or more, and is then renewed at shorter intervals, the degree of abduction being diminished at each renewal until the limbs are nearly parallel. The child is only kept in bed for a week or two, and is then allowed up, being provided with a boot and high sole on the affected side, but should not use crutches. At the end of six months, by which time the capsule has become tightened up round the head of the femur, the plaster is given up and massage and exercises are employed.

_In bilateral cases_ both dislocations are reduced at one sitting if possible, and a plaster case applied with both thighs abducted and flexed to a right angle, the so-called "frog position."

In the event of failure to reduce a dislocation at the first attempt, the limb should be fixed in plaster in the abducted attitude for ten days or a fortnight, and then another attempt made. The greatest number of successes in bilateral cases is met with under five years of age, and in unilateral cases under seven. Reduction may sometimes be accomplished, however, in older children.

If it is found impossible to restore the head of the femur to the acetabulum, an attempt should be made by similar manipulations to wedge it under the long head of the rectus femoris, or, failing this, below the anterior iliac spine under the sartorius and tensor fasciae femoris. By thus converting a posterior into an anterior dislocation, the tilting of the pelvis and the lordosis are greatly diminished. This procedure, named by Lorenz _anterior transposition of the head of the femur_, is specially applicable to cases in which relapse has taken place after reduction, and to those above the age when reduction should be attempted.

_Reduction by open operation_ may be had recourse to in cases in which, after several attempts, reduction has failed, or in which re-dislocation has occurred; it is, however, a serious operation. Attempts have also been made by means of pegs and other contrivances to fix the head of the bone and prevent it sliding upwards on the ilium. When reduction is impossible by any means, a stiff leather jacket with prolongations around the thighs may diminish the deformity and improve the walking.

#Snapping Hip# (_Hanche a ressort_).--This is a rare affection, met with in children and young adults, and characterised by the occurrence of a sudden, snapping sound, sometimes attended with pain in the region of the great trochanter. This usually occurs when the limb is slightly flexed or adducted, and rotated either inwards or outwards. On palpation a cord-like structure may be felt, which slips forwards and backwards over the trochanter when the position of the limb is altered.

The condition was formerly described as a voluntary dislocation of the hip; it is now believed to be due to a cord-like band of tissue slipping backwards and forwards over the trochanter. The band is usually derived from the fascia lata, sometimes reinforced by the anterior fibres of the gluteus maximus, sometimes by the tensor fasciae femoris. The condition seldom gives rise to any appreciable disability and surgical treatment is rarely called for. In a number of cases the muscle has been fixed by sutures with satisfactory results. In a recent case, an extensive open dissection proved negative, but the stitching of the gluteus to the trochanter was followed by the disappearance of the snapping.

#Paralytic Deformities of the Hip.#--In anterior poliomyelitis the paralysis of muscles may be so widespread that the limb is unable to support the weight of the body, or certain groups of muscles only are paralysed and the child may be able to walk with the help of apparatus. Even if the ilio-psoas is paralysed, flexion is still possible by the anterior fibres of the gluteus medius, the anterior adductors, and when the leg is rotated out by the tensor fasciae and sartorius, the dislocation differs from the traumatic variety in that the head, although it leaves the socket, remains within the capsule. Dislocation tends to occur from the disturbance of muscular balance, anterior dislocation being commoner than posterior in about the proportion of two to one; the nature of the dislocation is best demonstrated by means of the X-rays. Reduction is rarely possible without an open operation. Tendon and nerve-transplantation are scarcely possible, and arthrodesis is rarely to be recommended; contracture deformities, however, are often benefited by tenotomy in young children, and in older children by osteotomy through the trochanter, and putting the limb up in the abducted position.

In _spastic paralysis_ of cerebral origin, the tendency is towards contracture, usually in the attitude of flexion, with adduction and inversion. This may result in dislocation backwards on to the dorsum ilii, and may occur in patients confined to bed (Fig. 131).

#Contractures and Ankyloses of the Hip.#--Various forms of contracture are met with as a result of cicatricial contraction, or from shortening of the fasciae, muscles, and ligaments when the hip has been maintained in the flexed position for long periods--for example, in psoas abscess, chronic rheumatism, or hysteria. The majority, however, result from tuberculous disease of the hip-joint. In osseous ankylosis, an attempt may be made to restore movement by the operation of Murphy, which consists in chiselling through the osseous junction between the bones, deepening the acetabulum if necessary, and then interposing between the bony surfaces a portion of fat-bearing fascia derived from the fascia lata over the great trochanter. The operation of Jones consists in detaching the great trochanter (the insertions of the glutei into it being left intact), dividing the neck of the femur, and then securing the separated portion of the trochanter to the proximal end of the neck to prevent union of the fragments.

COXA VARA AND COXA VALGA

These deformities depend on abnormalities of the angle of the neck of the femur; the average or normal elevation is 125 deg. for the adult and 135 deg. for the child; variations between 120 deg. and 140 deg. are considered normal. If the angle is less than 120 deg. the condition is one of coxa vara; if greater than 140 deg., coxa valga. The angle of inclination of the neck of the femur is dependent upon the adjustment of certain forces, namely, the weight of the body, the action of muscles, and the resistance of the bone. The most obvious cause of deviation of the neck from the normal angle is some condition which causes softening of the bone so that it yields under weight-pressure, the most common being partial fractures, rickets, and other diseases of the bone.

#Coxa Vara--Incurvation of the Neck of the Femur.#--There may be a simple adduction bend of the neck, the head sinking to, or even below, the level of the great trochanter (Fig. 132); or this may be combined with a curve of the neck, of which the convexity is upwards and forwards, so that the lower border of the neck is greatly shortened and the head approximated to the lesser trochanter. At the same time the shaft of the femur is adducted and rotated outwards.

_Adolescent Coxa Vara._--This, the most common clinical type, is met with in boys between the ages of twelve and eighteen. The _unilateral_ form is nearly always the result of injury to the neck of the femur or to the epiphysial junction, although the deformity may not show itself for months or a year or two after the injury. The deformity may be the first indication, or it is preceded by pain and stiffness; the patient complains of being easily tired, of difficulty in kneeling and sitting, difficulty in riding, and of an increasing limp in walking. On examination, the limb is found to be shortened, the great trochanter is displaced upwards and backwards and is unduly prominent, and the muscles of the buttock and thigh are a little smaller and softer than on the normal side. The limb is adducted, its normal range of abduction, and sometimes also of flexion, is restricted, and there is, as a rule, some degree of lateral rotation, so that the toes point outwards. It should be noted that the same picture--shortening with eversion and stiffness at the hip--results from the common fracture of the neck of the bone in old people. The adduction element of the deformity is partly compensated for by upward tilting of the pelvis on the affected side and curvature of the spine with its concavity towards the affected limb.

_When the condition is bilateral_ it is usually the result of disease in the bone, rickets most frequently in this country. The attitude and gait are highly characteristic, as the adducted and everted legs tend to cross each other at the knee, the deformity being of the scissors-like type (Fig. 134), and in extreme cases the patient is only able to walk with the aid of crutches.

_Diagnosis._--Pain in the hip and a limp in walking suggest _hip-joint disease_, but while in coxa vara the movements are chiefly restricted in the direction of abduction, in hip disease they are restricted or absent in all directions. From _congenital dislocation of the hip_ the diagnosis can usually be made by the history, the examination of the joint and of its movements; and by the Trendelenburg test (p. 252). In _sacro-iliac disease_, the pain and tenderness are over the sacro-iliac joint and the movements at the hip are free in all directions. Valuable evidence is obtained from skiagrams.

_Treatment._--In the early stages, especially if there is pain and tenderness, the patient must lie up and extension is applied in the abducted position of the limb; after a fortnight or so recourse is had to massage and exercises and the patient is allowed up for a little each day, attention being paid to flat-foot, which is a common accompaniment. When deformity is the prominent feature and interferes with locomotion it must be corrected. The bloodless method is to be preferred; under general anaesthesia, the shortened adductors are stretched or divided, and forcible movements are carried out in all directions, until the limb can be brought into an attitude of marked abduction and internal rotation. A plaster-case is then applied, from the pelvis to the middle of the calf, the knee being slightly flexed for greater comfort; in a week or so the patient is able to go about, and in a couple of months a second plaster-case is applied, this time leaving the knee free. After another six weeks or so a moulded splint is used, which can be removed at bedtime. The traumatic forms can nearly always be corrected by this bloodless method. In advanced cases the deformity can only be corrected by open operation, which consists in dividing the femur obliquely downwards and medially through the great trochanter, and, the adductor muscles having been ruptured or divided, the limb is put up in the abducted position along with, if required, powerful weight extension.

In cases of traumatic origin--epiphysial separation--Sprengel has obtained good results by forcibly abducting and internally rotating the limb under an anaesthetic, and then applying a plaster-case which extends down to the knee.

#Other Forms of Coxa Vara.#--In _rickety children_, coxa vara is most often associated with pronounced eversion of both lower extremities, without the capacity for abduction being necessarily restricted, and with but little impairment of function. The child should be treated for rickets, and put up in a double long splint with the limbs abducted and inverted.

In _arthritis deformans_ of the hip, it is not uncommon to have considerable depression of the head of the bone and diminution in the angle of its neck, with consequent restriction of abduction. Sometimes the upper end of the shaft is also curved.

In _osteomyelitis fibrosa_, involving the upper end of the femur, a gross form of coxa vara may be observed, of which a marked example is shown in figures on pp. 476, 478, Volume I.

The _congenital variety_ of coxa vara is due to various intra-uterine conditions, of which the chief is defective development of the upper end of the femur; as it does not manifest itself until the child begins to walk, the resemblance to congenital dislocation of the hip is very close.

#Coxa Valga.#--Coxa valga is the reverse of coxa vara, the angle at the neck of the femur being over 140 deg.. It is not nearly so important in practice as coxa vara. It may result from incomplete fractures or epiphysial separations, rickets, or various forms of osteomyelitis, but it is also a frequent accompaniment of other deformities, such as congenital dislocation of the hip and paralysis following anterior poliomyelitis. It is commoner in boys than in girls, and is more often single than bilateral. The limb is lengthened, abducted, and rotated outwards; there is flattening of the buttock, and the trochanter is depressed so that it lies below Nelaton's line. The patient is unable to adduct the limb, and shows a peculiar gait, which has frequently caused the condition to be mistaken for unilateral congenital dislocation at the hip.

In recent cases it may be possible under anaesthesia forcibly to adduct the limb and rotate it inwards, and to retain it in this position with a plaster bandage. In advanced cases the length of the limbs may be equalised by a high sole on the sound side, or by performing an osteotomy through the great trochanter.

THE REGION OF THE KNEE

#Congenital dislocation# at the knee-joint is rare; it is usually incomplete, and the patella is sometimes absent. The dislocation may be permanent, or may only occur from accidental movements of the limb. In some cases it can be produced at will by the patient or the surgeon. We have observed one such case in a professional cyclist in whom this capacity of partially dislocating the knee entailed no disability. When the child begins to walk, an apparatus which will prevent hyper-extension and lateral motion should be fitted to the limb.

#Congenital absence of the patella# usually complicates other abnormalities of the knee-joint. The tubercle of the tibia is prominent and the extensor tendon unusually thick. In flexion the tendon rises on to the lateral condyle of the femur.

#Congenital Dislocation of the Patella Laterally.#--This may be persistent or intermittent. In the _persistent form_ the dislocation is present from birth; the patella rests on the trochlear surface of the lateral condyle, and when the knee is flexed may pass farther outwards and become completely dislocated, lying against the lateral aspect of the condyle.

In _the intermittent_ or _recurrent_ form the patella lies in its normal place, but is liable to be displaced outwards when the joint is flexed; the displacement occurs suddenly and unexpectedly in walking, and the patient may fall to the ground, suffering intense pain. The knee-cap is readily replaced on extending the joint, but the sprain of the joint is followed by effusion, and the patient is usually disabled for a day or two. It is met with chiefly in girls, and there may be a history that the child was late in walking and learned with difficulty. On examination, the patella is found to have an abnormal range of movement outwards, although it cannot be completely dislocated without considerable pain. If the child is brought for advice when there is fluid in the joint, the condition is liable to be mistaken for tuberculous synovitis. The observation that the undue mobility of the knee-cap is present in both knees is of assistance in arriving at a diagnosis, and also the history that the girl has repeatedly hurt her knee in falling.

The cause of the abnormal mobility of the patella varies in different cases; in some there is congenital laxity of the ligaments, in others a faulty formation of the lower end of the femur. Bade has observed families in which several children were affected, and although there was nothing abnormal in the shape of the bones, the knee was slender and delicately formed.

The use of a strong knee-cap may prevent falling, but as a rule an operation is required, and there is quite a number to choose from, the principle of them all being to prevent displacement of the bone without unduly restricting flexion of the joint. That devised by Goldthwait consists in exposing, by means of a vertical incision, the whole length of the patellar ligament, splitting it longitudinally, separating the lateral half from the tibia, passing it under the medial portion and suturing it to the periosteum; this gives the quadriceps a straight line of pull. We have achieved the same result by dividing the lax capsule and synovial membrane on the medial side of the patella, and overlapping the edges with a double line of catgut sutures.

Lateral dislocation of the patella is met with in extreme forms of _knock-knee_, and after correction of this deformity by osteotomy, and its possible occurrence should be guarded against at the time of the operation.

#Genu Recurvatum.#--In this deformity the knee is hyper-extended, the thigh and leg forming an angle which is open forwards; the attitude may be permanent or may only appear on walking. It is an extremely disabling and unsightly deformity.

There are several varieties. In the _congenital form_, which is apparently due to a faulty attitude of the lower extremities _in utero_, the patella may be imperfectly developed or absent; the knee is convex backwards, and attempts to flex the joint cause pain. Other deformities frequently coexist. The treatment consists in flexing the joint to a right angle under an anaesthetic, and maintaining this attitude by means of plaster-of-Paris or splints until the growth of parts overcomes any tendency to relapse.

_Acquired Forms._--The most common acquired form is the result of anterior poliomyelitis, and is described in the next section.

The deformity may also be due to rickets which has caused a backward bend of the tibia immediately below its upper epiphysis--sometimes combined with an exaggerated forward curve of the femur. If there is no prospect of spontaneous rectification, the upper end of the tibia should be divided with the osteotome, and the limb straightened.

It may result also from fracture or from separation of one of the epiphyses in the region of the knee, or from cicatricial contraction of the quadriceps. As a result of bone and joint disease, it is met with chiefly in neuro-arthropathies when the knee has become disorganised and flail-like.

#Deformities of the Knee resulting from Anterior Poliomyelitis and from Spastic Paralysis.#--When there is paralysis of all the muscles acting on the knee, the joint may be so flail-like that the patient is unable to stand without the aid of a crutch, or when weight is put on the limb, it assumes the attitude of genu recurvatum. The usefulness of the limb may be improved by the application of a rigid apparatus with a lock at the joint so that it can be used in the extended position for walking or in the flexed position for sitting. The rigid knee produced by arthrodesis affords good support but is inconvenient in sitting.

When the _quadriceps alone_ is paralysed, the patient is obliged to maintain the joint in the position of extreme extension, because the least degree of flexion results in the limb giving way under him. In course of time the posterior ligament is stretched, and the joint becomes hyper-extended, acquiring the attitude of _genu recurvatum_. When it is bilateral the gait is seriously impaired. The treatment consists in applying an apparatus which prevents hyper-extension, in improving the condition of the thigh muscles, and in wearing a splint at night which secures the flexed position. Recourse may be had to operative measures, such as transplanting one of the hamstrings into the patella, so as to compensate for the loss of power in the quadriceps, arthrodesis, or supra-condylar osteotomy of the femur.

When the quadriceps is overcome by a _contraction of the hamstrings_, as in spastic paraplegia, the knee is fixed in the flexed position and the child is unable to walk. The flexion may be corrected by lengthening the hamstring tendons, bringing the divided biceps tendon through an opening in the vastus lateralis, and attaching it to the rectus and to the patella. If there is a combination of flexion and genu valgum, the knee-joint should be resected and ankylosed in the straight position.

#Contracture and Ankylosis at the Knee.#--In addition to the different paralytic forms above described, contracture may result from ulceration and suppuration in the popliteal space, and from disease (osteomyelitis) in one of the adjacent bones. The greater number of contractures and ankyloses are the result of disease in the joint, and have already been described.

GENU VALGUM AND GENU VARUM

In the normal limb, a line drawn from the centre of the head of the femur to a point midway between the malleoli passes through the centre of the knee-joint. If the line passes outside the centre of the knee-joint, the condition is one of genu valgum; if inside, it is one of genu varum (Fig. 135).

#Genu Valgum--Knock-knee.#--In this deformity the leg joins the thigh at an angle which is open outwards, and when the affection is bilateral, the projecting knees tend to knock against each other in walking; the term X-legs is sometimes applied to it.

_Etiology._--The observations of Macewen and of Mikulicz, and information afforded by the Roentgen rays, have shown that the primary cause of the deformity is an inequality of growth at the ossifying junction of the femur or tibia or of both. This inequality of growth is nearly always due to rickets, and its direction is determined by a faulty attitude of the limbs in standing and walking. The legs being abducted, the weight of the body falls unequally on the medial and lateral parts of the ossifying junctions, and inequality of growth results.

_Pathological Anatomy._--Examination of the femur usually shows that the lower third of the diaphysis is lengthened on its medial side and shortened on its lateral side, and that the epiphysis, itself unaltered, is fitted on to the diaphysis obliquely, so that the medial condyle appears to be increased in length and to occupy a level distinctly below that of the lateral condyle. In many cases the tibia shows corresponding alterations. On section of the bones, the epiphysial cartilage and the zone of ossification are found to be unduly broad and irregular.

The neck of the femur is shortened and its angle diminished. The bones of the leg are sometimes bent inwards in their lower thirds, and this compensates partly for the valgus deformity at the knee. The articular cartilage of the lateral condyle and the lateral meniscus are usually thickened. In pronounced cases the quadriceps tendon and the patella are displaced laterally, and this may be so pronounced that on flexion of the joint the patella is dislocated on to the lateral condyle of the femur. The biceps tendon and ilio-tibial band are shortened and more prominent as a result of the approximation of their attachments, and they are also displaced laterally. The sartorius and gracilis are displaced backwards, so that they descend behind instead of on the medial side of the knee. The popliteal artery lies on the back of the lateral condyle instead of in the hollow between the condyles, and the tibial (internal popliteal) nerve is displaced even farther outwards. The capsular and other ligaments are slack, so that the joint is unstable and easily hyper-extended. There is often some effusion into the joint.

_Radiograms_ reveal the changes in the bones (Fig. 138); the shaft of the femur or tibia, or both, which may also be curved, is set obliquely on its epiphysis; and the clear zone, corresponding to the epiphysial cartilage, is uneven and broader than normal. There are also less obvious changes in the density of the shadow and in the arrangement of the trabecular structure of the bones.

_Clinical Features._--In the infantile form (Fig. 139) the knock-knee is commonly associated with rickets in other parts of the skeleton, and especially with bending of the tibia and femur, and in extreme cases the child may be unable to walk.

The deformity is about as frequently bilateral as unilateral. There may be knock-knee on the one side and bow-knee on the other. If, as is usually the case, the deformity is due to obliquity of the femur, it disappears on flexing the joint (Fig. 140), because in flexion the tibia glides behind the projecting median condyle; if the deformity affects the tibia only, the influence of flexion in disguising it is not so marked. It is usually possible to hyper-extend the joint, and, in the extended position, to rotate the leg outwards to a greater extent than is normal. In unilateral knock-knee, the affected limb is a little shorter than its fellow, but the patient compensates for this by depressing the pelvis on the affected side.

_Prognosis._--In children below the age of six, the bones naturally tend to straighten if the child is kept off its feet. After this age, there is no such prospect.

The _treatment of knock-knee in children_ is directed towards curing the rickets and preventing the child from putting its feet to the ground. If it cannot have the services of a nurse and the use of a perambulator, a light padded splint is applied on the lateral side of the limb, extending from the iliac crest to 3 inches beyond the foot. The splint is fixed above and below by bandages, and the projecting knee is drawn towards it by a few turns of elastic webbing. A method specially applicable to hospital out-patients, is to straighten the limbs as far as possible under anaesthesia, and apply a plaster bandage; the bandage is renewed at intervals of three weeks until the deformity is corrected. Whatever plan is adopted, it must be persevered with for at least six months, until the rickety changes in the bones have been entirely recovered from.

If the child is approaching the age of five or six before it comes under treatment, or if the deformity does not yield to treatment by splints, it is better to straighten the limb by _osteotomy_.

In _adolescent knock-knee_ the patient seeks advice because of the deformity or of pain after exertion, especially at the medial side of the epiphysial junctions, of being easily tired, and of incapacity for any occupation involving standing. The bones are coarse and badly formed, and there is frequently a spinous process projecting downwards from the medial side of the tibia about three finger-breadths below the joint.

When the deformity is bilateral, the patient abducts the thigh and rotates the limb outwards at the hip to disguise the deformity, and to allow the projecting knees to pass each other. He usually supinates or inverts the foot, with the object of bringing the whole length of the lateral border of the sole into contact with the ground. Flat-foot is exceptional. The boots are usually more worn along the lateral than along the medial border of the sole and heel.

No apparatus that allows of the patient walking is of any value. If the deformity is marked, there should be no hesitation in having recourse to operation by one or other of the various methods of osteotomy.

In severe cases it may be found that when the deformity is corrected by osteotomy, the patella shows a tendency to be dislocated laterally on flexion of the knee. This may be prevented by putting up the limb in the attitude of slight genu varum.

The most difficult cases to treat are those in which, owing to curving of the lower part of the shaft of the femur with the convexity forwards, the knee is permanently flexed and cannot be completely extended.

#Other forms of genu valgum# are relatively rare. There is a congenital form arising from faulty position of the limbs _in utero_; a traumatic form following fracture or epiphysial separation in the region of the knee; and a paralytic form, usually combined with flexion, in cases of spastic paralysis. Finally, genu valgum may be a result of various forms of osteomyelitis of the lower end of the femur, or of disease in the knee-joint, such as tuberculosis, arthritis deformans, or Charcot's disease.

#Genu Varum--Bow-knee.#--In this deformity, which is the converse of genu valgum, the leg joins the thigh at an angle which is open medially. It is almost invariably bilateral, is of rachitic origin, and is frequently associated with bow-legs (Fig. 141). The tibia takes a greater share in its production than the femur. Although an ungainly deformity, it is much less frequently the source of complaint than knock-knee, because it scarcely interferes with locomotion--as a matter of fact, the subjects of bow-knee, although short in stature, are unusually sturdy on their legs. An extreme example of the deformity is shown in Fig. 141.

Treatment is carried out on the same lines as in genu valgum.

#Rickety Deformities of the Bones of the Leg--Bow-leg.#--These deformities are common in children; are nearly always bilateral and symmetrical, and may be associated with knock-knee or bow-knee. They may occur before the child is able to walk, the bones bending in the attitude in which the limbs are habitually placed--over the nurse's knee, for example, or as they are crossed underneath the child in sitting. In children who are able to walk, the curve is due to the weight of the body acting on the softened bones. In either case, the bending may be increased by the traction of muscles, and sometimes by the occurrence of greenstick fracture. The most common deformity is a uniform curvature of the bones laterally and forwards, or a more acute bend in the lower thirds of their shafts. In some cases the chief curvature is forwards. The ungainliness in walking may be added to by flat-foot. Backward curving of the upper end of the tibia has been already described as one of the causes of genu recurvatum. The most extreme deformities are met with in rickety dwarfs.

_Treatment._--Under the age of six, and particularly in children, who are actively growing, the bones will probably straighten if the child is treated for rickets and kept off his feet; well-padded lateral splints are applied as recommended for knock-knee, and these should be taken off at intervals for massage and douching. Above the age of six, the choice lies between osteoclasis and osteotomy. In performing osteotomy the bone is either simply divided or a segment is resected. The fibula can usually be forcibly straightened, but may require to be divided through a separate incision. In aggravated cases it may also be necessary to lengthen the tendo Achillis.

The deformities of the bones of the leg in _inherited syphilis_, _ostitis deformans_, and _osteomalacia_ have already been described.

#Congenital Deficiencies of the Bones of the Leg.#--The _tibia_ may be absent completely or in part, more often on one side than on both sides. In either case the leg is short and stunted, the knee is flexed, the foot occupies the position of extreme equino-varus, and the limb is useless. The extent of the defects is demonstrated by the Roentgen rays. Among other defects with which it may be associated, absence or deficient development of the patella is the most frequent. When the upper end of the tibia is absent, the fibula articulates with the lateral condyle of the femur. The operative treatment aims at correcting the flexion at the knee, the equino-varus deformity of the foot, and at substituting the fibula for the absent tibia. The deficiency of the upper end may be compensated for by implanting the head of the fibula between the condyles of the femur, and that at the lower end by splitting the fibula so as to form a socket for the talus. Amputation should be avoided, as even a dwarfed leg and foot improves the service of an artificial limb. A modification of the O'Connor extension boot may be employed.

The _fibula_ may be absent completely or in part. The clinical appearances depend upon the condition of the tibia. When the tibia is normal, the most notable feature is the absence of the lateral malleolus, and the extreme valgus attitude of the foot. More commonly the tibia makes a sharp forward bend just below its middle, and the overlying skin presents a dimple or scar-like depression. This has usually been regarded as an evidence of intra-uterine fracture, but the observations of Hoffa suggest that both the bend of the bone and the depression on the skin are due to pressure exercised upon the leg from without by an amniotic band or adhesion. The leg fails to grow, the deformity becomes more pronounced, and the toes become pointed. If the tibia is markedly bent, it may be straightened by osteotomy; and the tendons, Achillis and peronei, may require to be lengthened. If the ankle is unstable as a result of the absence of the lateral malleolus, it may be artificially ankylosed, or the lower end of the tibia may be split vertically so as to make a socket for the talus. In either case, the foot is placed in the equinus attitude to compensate for the shortening of the leg. Deficiency of the tibia is frequently associated with imperfect development of the great toe; deficiency of the fibula with absence of the lateral toes and their metatarsal bones.

_Volkmann's Supra-malleolar Deformity._--This condition, which is closely allied to that just described, consists in a congenital deficiency in the development of the bones of the leg, and especially of the fibula, as a result of which the articular surface is oblique and the foot deviates to one or other side. The foot usually occupies a valgus position, the sole looking laterally, and only its medial border coming into contact with the ground. It is treated by supra-malleolar osteotomy.

THE FOOT

Various deformities are met with in the region of the ankle and tarsus. The term "talipes" is commonly used to include all these, but here it will be restricted to that form in which the heel is more or less elevated, and the foot supinated so that it rests on its lateral border--_talipes equino-varus_. In _pes equinus_ the foot is in the position of plantar-flexion, and the patient walks on the toes. In _pes calcaneus_ the foot is dorsiflexed so that the tip of the heel comes in contact with the ground; this deformity may be combined with eversion of the foot, _pes calcaneo-valgus_, or with inversion, _pes calcaneo-varus_. When the instep is unduly arched, the terms _pes cavus_, _pes arcuatus_ or _hollow claw-foot_ are employed; while loss of the arch constitutes _flat-foot_, and eversion of the sole, _pes valgus_.

CLUB-FOOT

#Talipes Equino-varus.#--This deformity may be congenital or acquired.

#Congenital talipes equino-varus# (Fig. 142) is a common malformation which is sometimes associated with other deformities, such as hare-lip or spina bifida, and may be met with in several members of one family. It is nearly twice as common in boys as in girls, and is slightly more frequently bilateral than unilateral. Its etiology is obscure, and various hypotheses have been put forward to account for it, but no one is convincing. It may be pointed out, however, that the foetal foot is very easily moulded into abnormal attitudes by external pressure such as might be exercised by the wall of the uterus when the liquor amnii is deficient. In a number of cases there are indications of such pressure over the bony prominences of the foot, in the shape of circumscribed scar-like areas in which the skin is atrophied; and in the infant, the intra-uterine position can be reproduced, thus demonstrating its method of origin. The occurrence of club-foot in several generations is alleged to support the Mendelian law.

_Pathological Anatomy._--In well-marked cases the foot presents a concavity towards the medial side, the maximum point of the curve being opposite the mid-tarsal joint. When the patient attempts to stand, only the lateral border of the foot touches the ground, and the weight is borne on the fifth metatarsal, the cuboid, and the greater process of the calcaneus.

The individual tarsal bones, especially the talus and calcaneus, are altered in shape as well as in their relations to one another and to the tibio-fibular socket. The navicular and cuboid are rotated medially around the anterior ends of the talus and calcaneus respectively, and the tubercle of the navicular comes to lie close to the medial malleolus. The lower third of the tibia is twisted medially on its vertical axis.

The changes in the soft parts follow the general law that tissues which are relaxed become shortened, while those that are put on the stretch are lengthened. All the tissues on the medial, concave side of the foot are shortened, the structures most affected being the medial and the posterior ligaments of the ankle, and the inferior calcaneo-navicular ligament. There is also shortening of the muscles inserted into the tendo Achillis, and to a less extent of the tibiales anterior and posterior. The extensor tendons on the dorsum are displaced medially.

_Clinical Features._--_In children who have not walked_, the degree of deformity varies, sometimes being very slight; in pronounced cases, the foot is turned medially, and in that position forms a right angle with the leg; the sole looks backwards and the medial border upwards. The foot appears shortened because it is curved on itself, the heel is narrower and more vertical than normal, the medial malleolus is obscured by the approximation of the navicular, and the lateral malleolus is unduly prominent.

In extreme cases, the supinated foot forms an acute angle with the leg, and there is frequently a deep transverse depression across the sole, the result of contraction of the plantar fascia--a feature which is distinctive of the congenital form of club-foot.

_In children who have walked_, the deformity becomes aggravated. The dorsum of the foot is markedly uneven, partly because of the prominence of the individual tarsal bones, and especially of the head of the talus and greater process of the calcaneus, and partly because of a depression over the neck of the talus. Instead of resting on its lateral border, the foot may finally rest on the dorsum, the sole looking upwards and backwards. While the skin over the heel remains comparatively thin and delicate, that covering the lateral border and dorsum of the foot becomes the seat of callosities, beneath which adventitious bursae are formed. These bursae are liable to become inflamed, and are then a source of great suffering, and if they suppurate may cause persistent sinuses. The muscles of the leg and foot, although not paralysed, undergo atrophy from disuse. In walking, the patient lifts one foot over the other in an ungainly and laborious manner, without any spring, as if walking on stilts.

_In adults_, these features are further aggravated, and there are permanent changes in the bones (Fig. 144).

_Treatment._--This should be commenced as soon as the viability of the infant is beyond question, as the younger the patient the more easily and completely is the deformity rectified. Manipulations to correct the deformity should be carried out twice or thrice daily, and the limbs are also massaged and douched. At the end of two or three months, assistance may be derived from the use of a simple lateral poroplastic or aluminium splint with a foot-piece, or more simply by a strip of rubber plaster. The foot is held in the over-corrected attitude and the plaster is applied so as to maintain this attitude. If this regime is systematically persevered with from within a few days after birth, by the time the child begins to walk the sole can be brought into contact with the ground, and the weight of the body will aid in correcting the deformity. If the equinus element resists correction, the tendo Achillis should be lengthened.

The turning in of the toes may be overcome by strapping the feet at night to a wooden board with the whole lower limb rotated laterally so that the toes of each foot point directly outwards. On account of the tendency towards relapse, the manipulations and massage must be persevered with for at least a year.

_Tenotomy and Forcible Correction under Anaesthesia._--In more severe cases we have to deal not only with the contracted soft parts, but with changes in the bones resulting from their having grown in adaptation to the deformed attitude. The majority of surgeons defer operative measures until the child is about a year old.

The soft parts to be divided are the tendo Achillis, the medial and posterior ligaments of the ankle, the plantar fascia, the calcaneo-navicular ligaments, and the tibialis posterior tendon. The varus deformity may then be corrected by laying the foot on its lateral side on a padded triangular wooden block, and pressing forcibly on the anterior and posterior ends of the foot so as to undo the curve on its medial side and allow of abduction of the foot; this is usually attended with cracking as the shortened ligaments give way. The equinus element is next dealt with by forcibly dorsiflexing the foot until the deformity is over-corrected. If it is preferred to correct the deformity in stages instead of at one sitting, the equinus element is left to the last. In older children, the strength of the hands is usually insufficient to stretch the tissues, and mechanical wrenches may be employed, such as those devised by Thomas, Bradford, or Lorenz.

_Resection of a wedge from the tarsus_ (Davies Colley, 1876) is reserved for the most severe cases in which the shape and rigidity of the bones prevent correction of the deformity by any other means. The base of the wedge is on the lateral aspect, and the bone removed includes parts of the calcaneus, cuboid, talus, and navicular.

_Removal of the talus_ is an alternative operation to resection of the tarsus, and may yield equally good results.

In children, before the tarsal bones have become completely ossified, Ogston's method yields good results; instead of removing a wedge from the tarsus, the osseous nucleus of each bone is gouged out, leaving the cartilaginous shell. In this way the intertarsal joints are not interfered with, and the cartilaginous tarsus can be moulded so that when ossification is completed the bones differ but little from the normal.

After any of these operative procedures, manipulations, massage, exercises, electrical stimulation of the muscles, and the wearing of some apparatus must be persevered with for at least twelve months. Failures are due to not sufficiently over-correcting the deformity in the first instance, and to neglect of after-treatment; in hospital practice it is difficult to ensure continuous supervision over long periods.

Finally, _amputation_ may be called for when other methods have failed, and the patient is unable to put the foot to the ground because of suppurating bursae and ulceration of the skin.

#Acquired Talipes Equino-varus.#--In the great majority of cases this condition results from anterior poliomyelitis. It especially affects the peronei and the extensors of the toes, and is unilateral. The patient is unable to dorsiflex and abduct the foot, which hangs with the toes pointed and the sole turned medially.

At first the joints are flaccid, and the attitude can easily be corrected by manipulation. In course of time, however, the opposing muscles--those inserted into the tendo Achillis, the tibialis posterior, and the long flexors of the toes--become shortened, and there is secondary contraction of the plantar fascia and of the ligaments on the medial side of the foot, and the deformity is thus rendered permanent. The bones also are altered in their shape and mutual relations, the talus being rotated forwards so that a large portion of its trochlear surface protrudes from the tibio-fibular socket. The skin is cold and livid, and readily suffers from pressure sores. The whole limb is ill-developed, and may be shorter than its fellow, and the paralysed muscles are wasted and exhibit for a time the reaction of degeneration.

A similar deformity may result from section of the peroneal (external popliteal) nerve, from the peroneal form of progressive muscular atrophy, and from peripheral neuritis.

The _treatment_ of paralytic equino-varus, short of operation, has been referred to under anterior poliomyelitis (p. 242). If tendon transplantation is indicated, the tendon of the tibialis anterior is attached to the cuboid, and a strip of the tendo Achillis to the dorsal aspect of the tarsus. Jones displaces the tibialis anterior into the base of the fifth metatarsal.

If the paralysis is widely distributed, and the joints are flail-like, it is better to ankylose the ankle and mid-tarsal joints. It may be necessary to divide in several places the plantar fascia and other structures that have undergone secondary shortening.

As using the limb hastens the restoration of function, the child should be got on to his feet as soon as possible.

The spastic form of talipes equino-varus is comparatively rare. The plantar flexors and invertors distort the foot into the equino-varus attitude. The heel is drawn up, the anterior part of the foot is adducted and inverted at the mid-tarsal joint. The muscles are tense and rigid, and the reflexes exaggerated. The condition is frequently bilateral, and is often associated with other deformities of the lower limb and with a characteristic spastic gait. Considerable improvement may be brought about by lengthening the tendons of the shortened muscles. In severe cases it may be necessary to resect a portion of the tarsus.

The occurrence of #varus without equinus# is so exceptional as not to call for separate description.

#Pes Equinus.#--This deformity, in which the foot is in the position of plantar-flexion with the heel drawn up and the toes pointed, is nearly always acquired as a result either of poliomyelitis or of spastic paralysis. In typical cases the patient walks on the balls of the toes (Fig. 145). It is seldom met with as a congenital condition. Occasionally it is due to nerve lesions such as peripheral neuritis, or to injuries and diseases in the region of the ankle, when the foot has been allowed to remain for long periods in the attitude of plantar-flexion. In a limited number of cases the equinus attitude is assumed to compensate for shortening of the limb.

In _poliomyelitis_ the deformity is most often unilateral (Fig. 146), while in _spastic paralysis_ it is frequently bilateral (Fig. 145), and is usually accompanied by excessive arching of the foot--pes cavus--as a result of plantar-flexion at the mid-tarsal joint, and hyper-extension of the first phalanges and plantar-flexion of the second and third phalanges of the toes--"clawing of the toes."

_Clinical Features._--In the mildest cases the patient is able to bring the foot to a right angle. In average cases the heel is raised off the ground, and the foot rests on the balls of the toes. In extreme cases, and especially when the extensors are completely paralysed, the toes may be flexed towards the sole, and the weight is borne on the dorsum of the foot (Fig. 146). The patient suffers from painful corns and callosities, and from inflammation of bursae which form over the points of pressure. When unilateral, the patient compensates for the lengthening of the limb by flexing the knee and throwing the limb outwards in walking. In severe cases, especially when both limbs are affected, the patient may be dependent on crutches.

The talus projects on the dorsum, the anterior part of its trochlear surface escapes from the tibio-fibular socket, and the calcaneus is drawn up so that it comes into contact with the bones of the leg (Fig. 147).

Shortening of the soft parts affects chiefly the muscles inserted into the tendo Achillis, the posterior ligament, and posterior parts of the lateral ligaments of the ankle. The fasciae, ligaments, and muscles of the sole of the foot are also shortened. The flexors of the toes, the tibialis posterior, and the peroneus longus are shortened to a less degree.

_Treatment._--Of all the deformities of the foot, pes equinus is that most easily rectified. In recent cases a great deal may be done by regular manipulations, and by the wearing of some corrective splint or apparatus between times.

In well-marked cases it is necessary to lengthen the shortened structures, and especially the tendo Achillis. When the equinus is corrected, the excessive arching of the foot (pes cavus) and the clawing of the toes usually disappear, but it may be necessary to lengthen the flexor tendons, especially that of the great toe, and also the plantar fascia.

Jones divides the tendo Achillis and the flexors of the toes subcutaneously, and maintains the dorsiflexion by excising an oval flap of skin from the front of the ankle.

In aggravated cases, the bones must be attacked, for example by excising the talus. Arthrodesis of the ankle alone or along with the mid-tarsal joint may be indicated when these joints are flail-like. Amputation is reserved for cases which are otherwise hopeless, such as that shown in Fig. 147.

When the deformity is compensatory to shortening of the limb, it is usually said to be a mistake to correct the equinus. Experience shows, however, that in young patients growth is stimulated by walking on the limb after the deformity has been corrected; the sole of the boot is then raised to the necessary extent.

#Pes Calcaneus.#--In this deformity the foot is dorsiflexed at the ankle-joint. It is sometimes combined with eversion of the foot--_pes calcaneo-valgus_, or with inversion--_pes calcaneo-varus_.

Pes calcaneus may be congenital or acquired. In the _congenital form_ the deformity is frequently bilateral. There is dorsiflexion at the ankle-joint, and if an attempt is made to flex the foot towards the sole, the extensor tendons stand out prominently. In marked cases the long axis of the calcaneus is vertical, the tendo Achillis lies in close contact with the tibia, and the hollows on either side of the tendon are absent. The peronei are displaced from their grooves, and may lie in front of the lateral malleolus.

Corrective manipulations are commenced within a few days after birth, and a malleable splint is worn between times. When the child begins to walk there is a natural tendency towards recovery. In severe cases it may be necessary to lengthen the contracted tendons--the extensor digitorum, the extensor hallucis, and, it may be also, the peroneus tertius and tibialis anterior; the tendo Achillis may require to be shortened.

In the _acquired form_, the appearances are different, because the anterior part of the foot is usually flexed towards the sole, thus disguising to a certain extent the dorsiflexion at the ankle. This form is nearly always due to poliomyelitis, but it may also result from accidental division of the tendo Achillis. The anterior part of the foot is flexed towards the sole by the contraction of the plantar fascia and short muscles of the sole, the balls of the toes are approximated to the heel, and a deep transverse groove is formed in the sole opposite the mid-tarsal joint. The deformity presents a combination of the hollow foot--pes cavus--with pes calcaneus, and resembles that of a Chinese lady's foot. The foot rests on the heel and on the balls of the great and little toes, the sole of the foot being so deeply hollowed that even the lateral border does not touch the ground.

In paralysis of the calf muscles alone, the tendons of the peronei or flexor digitorum longus may be divided and stitched to the calcaneus, to take the place of the tendo Achillis. If the calf muscles are not completely paralysed and the tendo Achillis is merely stretched, this tendon may be shortened by splitting it longitudinally and making the ends overlap, or its insertion may be displaced downwards. When the ankle is flail-like, it may be necessary to perform arthrodesis.

Jones gets rid of the cavus deformity by resecting a wedge with its base towards the dorsum from the middle of the tarsus; the foot is then placed in a position of extreme calcaneus, the dorsum coming into contact with the front of the leg. Four weeks later a wedge is taken from the posterior part of the talus large enough to bring the foot down to a right angle with the leg; the articular surfaces of the tibia and fibula being denuded of cartilage, ankylosis takes place in a good position.

#Pes Calcaneo-valgus.#--This deformity, which consists in a combination of dorsiflexion at the ankle and eversion of the foot, is as common as pure calcaneus (Figs. 148 and 149); the heel is depressed, the sole looks laterally, and its medial border is convex. Although it may be congenital, it is usually acquired as a result of poliomyelitis. The calf muscles are paralysed while the peronei retain their power, and, along with the tibialis anterior and the extensors of the toes, become secondarily contracted. Treatment is conducted on the same lines as in pes calcaneus, and the valgus may be controlled by implanting the peroneus brevis into the navicular.

#Pes Calcaneo-varus.#--In this rare deformity the heel is depressed and the sole of the foot looks inwards.

#Pes Cavus.#--In this deformity, which is known also as _hollow claw-foot_, _pes arcuatus_, or _pes excavatus_, the longitudinal arch of the foot is exaggerated as a result of the approximation of the balls of the toes to the heel (Fig. 150). It is most frequently met with as an addition to pes equinus or pes calcaneus of paralytic origin, and has already been described. There is a mild form which is congenital, and which is quite independent of paralysis; another variety occurs in diseases of the spinal cord, such as Friedreich's ataxia.

The name hollow claw-foot appropriately indicates the clinical appearances. The arch is exaggerated and the instep abnormally high; there is hyper-extension of the toes at the metatarso-phalangeal joints, and plantar-flexion at the inter-phalangeal joints; the plantar fascia and muscles are shortened. The footprint shows that neither border of the foot touches the ground. The patient complains of pain in the instep, of painful corns over the heads of the metatarsal bones, and of difficulty in getting properly fitting boots.

_Treatment_ should first be directed towards the equinus or calcaneus element of the deformity, for if these are corrected the cavus condition tends to disappear. Exercises and massage should be persevered with, and boots without heels should be worn. The contracted structures in the sole may require to be divided, either subcutaneously or by the open method, as a preliminary to forcible correction, and the hallucis tendon may be brought through the head of the first metatarsal. In aggravated cases the talus and the heads of the metatarsal bones may be excised.

FLAT-FOOT--PES PLANUS AND PES VALGUS

Flat-foot or splay-foot is that deformity in which there is loss of the arch, and the foot tends to be pronated and abducted. The term _pes planus_ is applicable when there is merely loss of the arch; _pes valgus_ when the foot is pronated and the sole looks laterally. Of all deformities of the foot, flat-foot is the one for which advice is most frequently sought; it is also a common complication of other disabilities of the foot and of the lower extremity. It is usually bilateral, and is about twice as common in the male as in the female. Various types are met with; they are known according to their cause, as static, congenital, traumatic, paralytic, rachitic, rheumatic, arthritic, gonorrhoeal, and tabetic.

#Static or Adolescent Flat-foot.#--This, by far the most common and important variety (Fig. 152), generally develops between the ages of fourteen and twenty. It is called static because the essential factor in its production is a disproportion between the weight of the body and the supporting power of the arch of the foot.

It is met with in rapidly growing children or adolescents of feeble muscular development and with long narrow feet, and those especially who, after leaving school, begin some occupation which entails much standing--such as that of a factory hand, message boy, or domestic servant. To enable him to stand with the least effort for long periods, the patient adopts an attitude which makes little demand on the muscles, and throws nearly all the strain of the body weight on the ligaments and bones of the feet. This, which has been called "the attitude of rest," consists in standing with the limbs apart, the knees slightly flexed, the legs slightly rotated laterally at the knee, and the feet pronated, with the toes pointing laterally. The most important local factors predisposing to flat-foot are weakness of those muscles which normally support the ankle and the tarsal arches, especially the tibiales; weakness of the ligaments of the foot; and softness of the tarsal bones. When these conditions are present and a faulty method of standing and walking is adopted, the undue strain to which the tendons and ligaments are exposed results in their being stretched; the bones are altered in position, and flat-foot results. The head of the talus is displaced medially, and is protruded between the calcaneus and navicular, tending to separate them from one another, stretching the inferior calcaneo-navicular ligament and causing the anterior part of the foot to be abducted. The plantar ligaments--especially the inferior calcaneo-navicular--are stretched and lengthened. In something like 80 per cent. there is the combined deformity--pes plano-valgus--in those who apply for treatment.

_Clinical Features._--The patient complains of being easily tired, and of pain in the foot after walking or standing. There is generally more pain before the appearance of the deformity than when it has developed, and at this stage it is not so easily recognised, and is apt to be called "rheumatism." The most common seat of pain is at the medial border of the foot behind the tubercle of the navicular, and this is due to stretching of the inferior calcaneo-navicular ligament. Pain is also complained of in the middle of the dorsum across the instep, from stretching of the interosseous ligaments. Later, there is pain over the greater process of the calcaneus in front of the lateral malleolus, from these bones coming into contact. There may be nocturnal cramp in the muscles of the leg and foot.

The faulty attitude of the foot in standing and walking is usually evident. The foot appears longer and broader than normal, and when the body weight is put on it, it spreads out with the toes extended until the entire sole is in contact with the ground. In advanced cases, the medial border of the foot may be actually convex. Below and in front of the prominent medial malleolus, the head of the talus forms a rounded eminence, and a little farther forwards and lower still is the projection of the tubercle of the navicular. The eversion of the foot as a whole is best seen from behind; if the central axis of the leg is prolonged downwards, it approaches the medial border of the heel instead of passing through its centre; or, stated differently, instead of the axis of the calcaneus being a continuation of that of the leg, it deviates laterally and the medial malleolus is abnormally prominent. When the eversion is more pronounced, the sole looks laterally and the tendons of the peronei stand out in relief. The anterior part of the foot is displaced laterally. Flat-foot is frequently associated with stiff great toe; the patient having lost the power of dorsiflexing the toe, the first phalanx and first metatarsal are in a straight line, instead of forming an angle open towards the dorsum.

The muscles of the leg are flabby and poorly developed. When the patient is seated and asked to move the foot in different directions, there is a characteristic stiffness, ungainliness, and restriction in the range of movement. The feet are usually cold and sweat excessively. The gait is slouching, and there is a want of spring and elasticity. The lengthening of the foot results in the tendons, especially the flexors, being too short, hence hammer-like contraction of the toes may be brought about. The boots, after being worn, show a bulging of the instep towards the sole, greater wearing away of the sole along the medial border, and, when there is stiff great toe, an absence of the transverse crease on the dorsum opposite the balls of the toes. Footprints may be obtained by wetting the soles of the feet. The print of a normal foot shows only the heel, the lateral border of the foot, and the balls and tips of the toes. In flat-foot the medial border appears in the print to a greater or less extent (Fig. 154). If a record is wanted to estimate the progress of treatment, the sole of the foot is painted with a 5 per cent. solution of ferro-cyanide of potassium, and the patient stands on paper painted with the liquor of the perchloride of iron diluted one-half; the print appears dark blue on a yellow ground.

_Skiagrams_ are useful for showing displacement of bones and differences between sitting and standing, and for recording the results of treatment.

_Prophylaxis of Flat-foot._--Stress is to be laid on a supervised training of the whole muscular system, and especially of that of the legs. In walking and standing, the feet should be kept parallel and not pointed outwards, as was formally taught in schools of gymnastics and insisted upon by drill instructors. Children should be taught to walk properly, rising on the balls of the toes with each foot in succession. Attention should also be directed to the boots, which should be so fashioned that the medial side of the boot is kept straight and the end of the boot is opposite the big toe.

_Treatment._--This is directed towards restoring and maintaining the arch of the foot. As the measures adopted necessarily vary with the extent to which the condition has progressed, it is convenient for purposes of treatment to recognise the following four degrees. A first degree, in which the arch reappears when the weight is taken off the foot or the patient rises on the balls of the toes; a second, in which the normal attitude can be restored by manipulation; a third, in which this is only possible under anaesthesia; a fourth, in which the bones are so displaced and altered in shape that correction is impossible without operation.

_Cases of the First Degree._--If there is marked pain and tenderness, the patient must lie up. The general health is improved by a nourishing diet and by cod-liver oil and tonics; and the legs and feet are douched and massaged thrice daily. When pain and tenderness have disappeared, the patient is instructed how to walk and exercise the feet. In walking, the medial edges of the feet should be parallel with one another, first the heel should touch the ground and then the balls of the toes. He should neither stand nor walk long enough to cause fatigue, and in standing he should alter the attitude of the feet from time to time, and occasionally rise on the balls of the toes. The following exercises, devised by Ellis of Gloucester, should be practised: (1) Rising on the balls of the toes, the toes being directed straight forwards; (2) rising on the balls of the toes, with the points of the great toes touching each other, and the heels directed out, so that the medial borders of the feet meet in front at a right angle; (3) in the same attitude, after rising on to the balls of the toes, the knees are flexed and then extended before the heels descend again; (4) while seated in a chair, one leg crossed over the other, circumduction movements of the foot are carried out; (5) while standing, the medial border of the foot is raised off the ground several times, then the patient walks to and fro on the lateral border of the foot, and in the same attitude lifts one foot over the other. These exercises should be carried out slowly and deliberately, with the feet bare, and they should be carefully supervised until the patient thoroughly understands what is aimed at. The movements should be performed a definite number of times at regular intervals, but should not be pushed so as to cause pain or fatigue. The patient should be fitted with well-made lacing boots, with the heel and sole raised about half an inch on the medial side so that the foot rests mainly on its lateral border. The additional leather, which can be applied by any bootmaker, is in the form of a wedge, with its base to the medial side, one on the sole and one on the heel. The wedge fades away towards the lateral border, and also forwards towards the tip. In time, the limbs are further strengthened by sea-bathing, cycling, skipping, and other exercises.

In _cases of the second degree_, the patient should be provided with a metal plate inside the boot. That known as Whitman's spring is the most popular. A plaster cast is taken of the sole while the foot is held in its proper position, and on this a metal plate, preferably of aluminium bronze, is modelled. This is covered with leather and inserted into the boot. We have found the supports devised by Scholl simple and efficient. The treatment described for cases of the first degree is carried out in addition.

In _cases of the third degree_, the deformity is corrected under an anaesthetic. The foot is forcibly moved in all directions so as to stretch the shortened ligaments and to break down adhesions, it is then rotated into an extreme varus position, and fixed in plaster-of-Paris or to a Dupuytren's splint. It may be necessary to have recourse to the Thomas' wrench, employed in the correction of club-foot. When the reaction consequent upon this procedure has subsided, the question of shortening or of reinforcing the tendons concerned in the support of the arch of the foot may be considered; one of the peronei, for example, may be attached to the tubercle of the navicular. We have not found it necessary to employ this procedure.

In _cases of the fourth degree_, in which the displacement and alterations in shape of the bones constitute an insuperable bar to correction, operative treatment may be considered, either resection of a wedge including the talo-navicular joint or forward displacement of the tuberosity of the calcaneus.

#Spasmodic Flat-foot.#--There are cases of flat-foot in which pain and spasm of the peronei muscles are the predominant features. If the spasm is not allayed by rest in bed and hot fomentations, the foot should be inverted under an anaesthetic; and in this position it is encased in plaster-of-Paris. Jones resects an inch of each of the peroneal tendons about 2-1/2 inches above the tip of the lateral malleolus; Armour and Dunn claim to have obtained better results from crushing the peroneal nerve in the substance of the peroneus longus.

#Paralytic Flat-foot# (Fig. 155).--In typical cases this results from poliomyelitis affecting the tibial muscles. When other groups of muscles are affected at the same time, compound deformities, such as pes calcaneo-valgus, are more likely to result.

In paralytic valgus the medial border of the foot is depressed and convex towards the sole, and although the foot can readily be restored to the normal position by manipulation, it at once resumes the valgus attitude. The leg is wasted, the skin is cold and livid, and the ankle is flail-like. The treatment consists in reinforcing the paralysed tibial muscles by attaching the peronei, or a strip of the tendo Achillis, to the scaphoid, or in bringing about an ankylosis of the joints above and in front of the talus.

#Traumatic flat-foot# is that form which results directly from injury. It is most often due to a fall from a height on to the feet; the ligaments supporting the arch are ruptured, and the bones are displaced, either at the time of the injury or later when the patient gets out of bed. The arch can only be restored by a wedge-resection of the tarsus. Loss of the arch may follow as a result of walking on the everted foot after injuries about the ankle, especially a badly united Pott's fracture; the foot may be displaced laterally and pronated, the sole looking laterally. This variety is very unsightly and disabling; it is treated by supra-malleolar osteotomy of the tibia and fibula.

#Other Forms of Flat-foot.#--Flat-foot is sometimes met with in rickety children, in association with knock-knee or curvature of the bones of the leg, and is treated on the same lines as other rickety deformities. It may follow upon an attack of acute rheumatism or upon diseases in the region of the ankle and tarsus, such as gonorrhoea, arthritis deformans, tuberculosis, and Charcot's disease; the gonorrhoeal flat-foot is extremely resistant to treatment. There is a congenital form in which the sole is convex and the dorsum concave, the result of the persistence of an abnormal attitude of the foetus _in utero_. Lastly, there is a racial variety, chiefly met with in the negro and in Jews, which is inherited and developmental, and which, although unsightly, is rarely a cause of disability.

#Pes Transverso-planus.#--Lange describes under this head a sinking or flattening of the anterior arch formed by the heads of the metatarsal bones, of which normally only the heads of the first and fifth rest on the ground. In this condition all may be on the same level or the arch is actually convex towards the sole. It may coexist along with the common form of flat-foot, or it may be associated with the neuralgic pain known as metatarsalgia.

#Painful Affections of the Heel.#--These include inflammation of the bursa between the posterior aspect of the calcaneus and the lower end of the tendo Achillis, inflammation of the tendon itself and its sheath of cellular tissue, and the presence of a spur of bone projecting from the plantar aspect of the tuberosity of the calcaneus. The spur of bone is the source of considerable pain on standing and walking, and tenderness is elicited on making pressure on the plantar aspect of the heel; it is well demonstrated by the X-rays (Fig. 156). The condition is usually bilateral. Complete relief is obtained by removing the spur by operation.

Sever of Boston calls attention to a painful condition of the heel met with in children, and associated with changes in the epiphysial junction, allied to those met with in the epiphysis of the tubercle of the tibia in Schlatter's disease. The changes in the epiphysial junction can be demonstrated in skiagrams. Treatment is conducted on the same lines as in teno-synovitis of the tendo Achillis.

#Metatarsalgia.#--This affection, which was first described by Morton of Philadelphia (1876), is a neuralgia on the area of the anterior metatarsal arch, specially located in the region of the heads of the third and fourth metatarsal bones. It is most often met with in adults between thirty and forty, is commoner in women than in men, and is often combined with flat-foot. The patient complains of a dull aching or of intense cramp-like pain in the anterior part of the foot. The pain is usually relieved by rest and by taking off the boot. It may be excited by pressing the heads of the metatarsals together or by grasping the fourth metatarso-phalangeal joint between the finger and thumb. In advanced cases the pain may be so severe as to cripple the patient, so that she is obliged to use a crutch. On examination, the sole may be found to be broadened across the balls of the toes, and there may be corns over the heads of the third and fourth metatarsals. Skiagrams may show a downward displacement of the head of one or other of these bones, and prints of the foot may show an increased area of contact in the region of the balls of the toes. The affection is of insidious development, and is usually ascribed to sinking of the transverse arch of the foot--pes transverso-planus--the result of weakness or of wearing badly fitting boots. The intense pain is believed to be due to stretching of, or pressure upon, the interdigital nerves or the communicating branch between the medial and lateral plantar nerves; Whitman believes it is due to abnormal side pressure on the depressed articulations.

_Treatment._--Great improvement usually results from treating coexisting flat-foot, and pain is relieved by rest, massage, and douching. A tight bandage or strip of plaster applied round the instep before putting on the stocking may relieve pain. Boots should be made from a plaster cast of the foot, high and narrow at the instep so as to compress the bases of the metatarsals, and with the medial edge of the sole and heel slightly raised; a support may be worn in the sole, like that used for flat-foot, with both the longitudinal and transverse arches exaggerated. Scholl has devised a support for the anterior arch which we have used with benefit. When the head of one of the metatarsals is displaced, it may be removed through a dorsal incision running parallel with the tendon of the long extensor.

#Hallux Valgus and Bunion.#--_Hallux valgus_ is that deformity in which the great toe deviates towards the middle line of the foot and comes to lie on the top of, or beneath, the second toe (Figs. 155, 157). The head of the first metatarsal projects on the medial border of the foot, and, as a result of the pressure of the boot, an adventitious bursa is formed, which, when thickened by chronic inflammation, constitutes a prominent swelling or _bunion_. It is a common affection in civilised and especially in urban communities, and reaches its acme of development in adult women. It may occur on one or on both sides, and is sometimes associated with flat-foot.

The deformity develops slowly, and is usually attributed to the wearing of stockings which are unduly tight at the toes, and of improperly made boots. The boot that favours the occurrence of hallux valgus is one which is too short and has pointed toes, with the apex in the middle line of the foot instead of being in line with the great toe. The pressure of the boot displaces the great toe into the valgus position, especially if a high heel is worn, as the toes are then driven forward into the apex of the boot. Once the great toe is abducted by the pressure of the boot, the deformity is increased by bearing unduly on the medial side of the ball of the great toe, and by pointing the foot outwards in walking.

Arthritis deformans is rarely the cause of hallux valgus, but the changes characteristic of that affection are commonly present in the joint of the great toe. In pronounced cases, the base of the first phalanx is displaced on to the lateral aspect of the head of the first metatarsal, the exposed head of which frequently shows fibrillation and wearing away of the cartilage, and is often surrounded by new bone, sometimes amounting to an exostosis. There are also fringes from the synovial membrane that may be caught between the articular surfaces. The distal end of the first metatarsal is displaced medially, broadening the tread of the foot, and in severe cases its shaft is rotated on its long axis, so that its dorsal surface looks medially; the great toe is then similarly rotated (Fig. 157). The flexor and extensor tendons and the sesamoid bones are displaced laterally. The ligaments and other soft parts on the medial side are elongated, while those on the lateral side are contracted.

In women, the chief complaint may be of the disfigurement of the boot; in others, of pain and disability resulting from the sensitiveness of the joint and of the enlarged bursa over the head of the first metatarsal. The inflamed bursa, which sometimes communicates with the joint, may suppurate, and the infection may spread to the joint.

The _treatment_ varies with the severity of the deformity. In mild cases, a great deal can be done by wearing properly made boots and stockings with a separate compartment for the great toe, or a pad of cotton wool or tent of rubber between the great and second toes. The patient should practise manipulations and exercises of the toes and feet, and putting the foot to the ground properly in walking. In pronounced cases, the pain and tenderness must first be got rid of by rest and soothing applications. At night, the attitude of the toe may be corrected by a moulded splint fixed to the medial aspect of the foot by strips of plaster; the toe is then bandaged to the distal end of the splint. Scholl has devised a prop, made of rubber, to be worn between the great and second toes. If there is flat-foot, this must receive appropriate treatment.

In aggravated cases, the deformity can only be corrected by an operation which consists in resecting the head of the metatarsal bone, and the tendon of the long extensor may be detached from its insertion and secured to the medial side of the first phalanx. A bar may be placed across the sole just behind the balls of the toes, and the boot should also comply with the anatomical shape of the foot.

#Hallux Varus or Pigeon-toe# (Fig. 158).--In this deformity, which is extremely rare, the great toe deviates from the middle line of the foot; it occurs chiefly in children in conjunction with other deformities, and interferes with the wearing of boots. Treatment consists in straightening the toe and retaining it in position by a splint or plaster of Paris. The medial collateral ligament and the tendon of the abductor hallucis may require to be divided.

#Hallux Rigidus and Hallux Flexus# (Fig. 159).--These terms indicate two stages of an affection of the metatarso-phalangeal joint of the great toe, first described by Davies Colley. In the earlier stage--_hallux rigidus_--the toe is stiff and incapable of being dorsiflexed, although plantar-flexion is, as a rule, but little restricted. When the joint, in addition to being stiff, is painful, sensitive, and swollen, the term _hallux dolorosus_ is applied.

As the disease progresses, the toe is drawn towards the sole and becomes permanently flexed--_hallux flexus_--and any attempt at dorsiflexion is attended with pain.

The condition is met with chiefly in adolescent males, is nearly always associated with flat-foot, and is then usually bilateral. The patient's gait, in addition to having the characteristic features associated with flat-foot, is peculiarly wooden and inelastic, as instead of rising on the balls of the toes with each step, he puts down and lifts the sole as if it were a rigid plate. The pain is increased by walking. The boot tends to become worn away at the point of the toes and at the posterior edge of the heel, and the usual crease across the dorsum is absent.

On dissection it is found, especially in hallux flexus, that the inferior portions of the collateral ligaments are contracted, and that the cartilage of that part of the head of the metatarsal which is exposed on the dorsum is converted into fibrous tissue; there may also be other changes characteristic of arthritis deformans. Bony ankylosis has not been observed.

_Treatment._--In early cases, great benefit results from measures directed towards the cure of the accompanying flat-foot, and especially the wearing of the support of the anterior arch devised by Scholl. If the joint of the big toe is painful and sensitive, absolute rest should be enforced until these symptoms have disappeared. The patient must wear a properly shaped boot with a pliable sole, and be instructed how to manipulate and exercise the toe. Later, when the toe is already rigid or flexed towards the sole, the above treatment is not feasible. It is then best to correct the deformity either by wrenching the toe into the dorsiflexed position, under anaesthesia, and fixing it with a plaster-of-Paris bandage; or, when this is impossible, by excising the articular end of the metatarsal bone and interposing a layer of fatty or bursal tissue between the distal end of the metatarsal and the base of the first phalanx. When these measures are impracticable, the suffering may be relieved by inserting in the boot a rigid metal plate which will prevent any attempt at dorsiflexion in walking.

#Hammer-toe.#--This is a flexion-contracture which generally involves the second, but sometimes also other toes. It may be congenital and inherited, but usually develops about puberty, and is then, as a rule, bilateral, and often associated with flat-foot.

The first phalanx is dorsiflexed, and the second is plantar-flexed, while the third varies in its attitude, sometimes being in line with the second (Fig. 160), sometimes even more plantar-flexed, and sometimes dorsiflexed. When the second toe alone is affected, as is commonly the case, it is partly buried by those on either side of it, only the knuckle of the first inter-phalangeal joint projecting above the level of the other toes (Fig. 160). The skin over the head of the first phalanx being pressed upon by the boot usually presents a corn, under which a bursa forms (Fig. 161). Both the corn and the bursa are subject to attacks of inflammation, which cause suffering and disability in walking. The soft parts at the distal extremity of the toe are flattened out by contact with the sole of the boot--hence the supposed resemblance to the head of a hammer.

On dissection, it is found that the contracture is maintained by shortening of the plantar portions of the collateral ligaments of the first inter-phalangeal joint and of the glenoid ligament upon which the head of the first phalanx rests.

Hammer-toe is usually ascribed to the use of tight socks and of ill-fitting boots, especially those which are median-pointed and are too short for the feet, but in some persons there appears to be an inherited predisposition to the deformity.

While corrective manipulations, strapping, and the use of splints may be of service in slight cases, it is usually necessary to perform an operation in order to extend the toe permanently. Before operating, any infective condition, such as a suppurating corn or bursa, must be corrected. The collateral and glenoid ligaments are divided subcutaneously--Spitzy also divides the flexor tendons and capsule--and if the toe can then be straightened, the foot is secured to a metal splint moulded to the sole and provided with longitudinal slots opposite the intervals on either side of the toe affected. The toe is drawn down to the splint by passing a loop of cotton or elastic bandage round the toe and through the slots. In many cases the contraction of all the tissues on the plantar aspect, including the skin, prevents the toe being straightened even after division of the ligaments, and it is then necessary to remove the head and neck of the first phalanx through a lateral incision. This is more satisfactory than amputation of the affected toe at the metatarso-phalangeal joint, as after this the adjacent toes tend to fall together and favour hallux valgus. If amputation is performed, a pad of cotton wool or rubber prop should be worn to fill up the vacant space.

The term _Gampsodactyly_ has been applied to a deformity in which all the toes assume the position of hammer-toe, usually from a spastic condition of the muscles controlling the toes.

#Hypertrophy of the Toes.#--One or more of the toes may be the seat of hypertrophy or local giantism. This is usually present at birth or appears in early childhood, and may form part of an overgrowth involving the entire lower extremity (Fig. 162). The overgrowth may involve all the tissues equally, or the subcutaneous fat may be specially affected. The medial toes are those most commonly hypertrophied. In addition to being enlarged, the toe may be displaced from its normal axis. The hypertrophy may affect two or more toes which are fused together or webbed (Fig. 162). The treatment consists in amputating as much of the toe as will allow of an ordinary boot being worn.

#Supernumerary Toes# (_Polydactylism_).--These vary from mere appendages of skin to fully developed toes (Fig. 163); if they interfere with the wearing of boots they should be removed.

#Webbing of the Toes# (_Syndactylism_).--This may affect two or more toes, which may be united merely by a web of skin, or so completely fused that the individual digits are only indicated by the nails; the degree of fusion is shown by means of skiagrams. Unless associated with congenital hypertrophy, no treatment is called for.

THE UPPER EXTREMITY

#Congenital Absence of the Clavicle.#--Both clavicles may be absent, and it is possible for the patient voluntarily to bring his shoulders into contact with one another in front of the chest; there is little or no impairment of function.

#Displacements of the Scapula.#--_Congenital Elevation of the Scapula_ (Sprengel's shoulder, 1891).--This abnormality is rare, and is not usually recognised till several years after birth. In one variety there is a bridge of bone or fibrous tissue connecting the superior angle of the scapula with the spinous process of one of the cervical vertebrae, and there may be a false joint at one end of the bridge permitting a certain amount of movement of the scapula. Associated abnormalities in the vertebrae and in the ribs are shown in skiagrams. In the more common type, the scapula seems to be held in its elevated position by shortening of the muscles attached to its body, and it is often rotated so that its lower angle is close to the spine and its axillary border nearly horizontal, or the axillary border may lie in close to the ribs, and the vertebral border project from the chest wall. The shoulder is generally higher and farther forward on the affected side, and there is a moderate degree of scoliosis. There is a want of purchase in the movements of the shoulder and upper arm.

When the deformity is bilateral, which is rare, the neck is short and thick, the chin lies close to the sternum, and the arms can scarcely be raised to the horizontal.

Gymnastic exercises and the wearing of a brace to hold the shoulders back and down may be followed by some improvement, but, as a rule, it is necessary to mobilise the scapula by operation. An X-ray photograph should first be taken, because, when the scapula is connected with the spine by a bridge of bone, this must be resected. The muscles attached to the vertebral border and spine of the scapula are divided, the bone is drawn down to its proper position, and the parts are fixed by plaster bandages.

_Winged Scapula._--This condition consists in a marked displacement backwards of the lower angle and vertebral border of the scapula, when the patient attempts to raise the arm from the side (Fig. 165). Under normal conditions, in making this movement the serratus and rhomboid muscles pull forward the vertebral border and inferior angle of the scapula, and so fix the bone firmly against the chest wall. When these muscles are paralysed, as a result of anterior poliomyelitis, neuritis, or injury of the long thoracic nerve of Bell, or of the fifth and sixth cervical nerve-roots through which they receive their supply, the patient is unable to abduct the arm, and the deltoid having lost its _point d'appui_, its contraction merely results in tilting the angle of the scapula backward (Fig. 165).

_Treatment._--In the majority of recent cases the condition yields to the administration of strychnin and other muscle and nerve tonics, and the use of massage and the faradic current. The application of a carefully adjusted padded belt is sometimes useful. The method of treatment by stitching the latissimus dorsi over the lower angle of the scapula is based on the erroneous assumption that the displacement is due to the slipping of that muscle off the bone; at the same time, it must be admitted that the operation sometimes diminishes the deformity and adds to the patient's comfort.

A more efficient method consists in detaching the clavicular portion of the pectoralis major from its insertion, and stitching it to the serratus anterior so as to make it take on the function of this muscle, or stitching it to the axillary border of the scapula. Success has also followed suture of the vertebral border of the scapula to the subjacent ribs (Eiselsberg).

_Displacement of the scapula upwards and laterally_ has been observed as a result of partial paralysis of the trapezius when the nerves supplying it have been divided in removing tuberculous glands from the neck. In these acquired displacements, treatment is directed towards the nerve lesion and towards the improvement of the muscles by electricity, massage, and exercises; when the paralysis of the trapezius is permanent, the disability is gradually overcome by the compensatory hypertrophy of the levator muscle.

#Congenital Dislocation of the Shoulder.#--This rare condition is usually bilateral, and is associated with other congenital defects. The glenoid cavity is deformed or absent, and the dislocation may be sub-coracoid, sub-acromial, or sub-spinous. The movements of the arm are restricted, and the development of the extremity as a whole is imperfect. It is sometimes possible to reduce the dislocation by manipulation, or, if this fails, by operation. Unilateral dislocation is sometimes mistaken for dislocation that has occurred during delivery and _vice versa_.

#Habitual Dislocation# is described on p. 65.

#Paralytic Deformities--Paralytic Dislocation of the Shoulder.#--The muscles in the region of the shoulder may have their innervation interfered with as a result of various conditions, of which poliomyelitis and injuries of the brachial plexus at birth are the most important. The capsular ligament of the shoulder-joint, being no longer kept tense by the scapular muscles--especially the deltoid and lateral rotators--becomes relaxed, and is gradually stretched by the weight of the arm. The appearances are characteristic; the muscles of the shoulder are wasted, the acromion is prominent, and between it and the upper end of the humerus there is a marked hollow into which one or more fingers may be inserted. The arm hangs flaccid by the side, rotated medially and pronated, and moves in a flail-like fashion in all directions, the patient having little control over it. The best results are obtained by the transplantation of muscles, the trapezius being detached from the clavicle and stitched to the surface of the deltoid, and the upper arm fixed in the position of horizontal abduction with the arm rotated laterally and supinated. Bradford inserts a portion of the trapezius into the humeral insertion of the deltoid. When these methods are impracticable, the upper arm may be fixed to the trunk by some form of apparatus, or arthrodesis is performed so that the movements of the scapula are communicated to the upper arm; the best attitude for ankylosis is one of abduction with medial rotation, so that the hand can be brought to the mouth.

In cases of poliomyelitis, when all the muscles governing the elbow are paralysed while the muscles of the hand have escaped, it may be of great service to fix this joint permanently at rather less than a right angle. This may be effected by arthrodesis, or by removing an extensive diamond-shaped portion of skin from the flexor aspect of the joint and bringing the raw surfaces together, commencing the stitching at the lateral apices of the gap.

#Congenital Dislocations at the Elbow.#--_The head of the radius_ may be dislocated forwards, backwards, or laterally--usually in association with imperfect development of the radius and of the lateral condyle of the humerus. When the displaced head of the bone interferes with supination, or with extension, it should be removed. Congenital dislocation of both bones of the forearm is extremely rare.

#Cubitus Valgus# and #Cubitus Varus#.--When the normal arm hangs by the side with the palm of the hand directed forward, the forearm and upper arm form an angle which is open outwards--known as the "carrying angle"; it is usually more marked in women in association with the greater breadth of the pelvis and the relative narrowness of the shoulders. When this angle is increased, the attitude is described as one of _cubitus valgus_. This deformity may be acquired as a result of rickets, but more commonly it is due to fracture of the lateral condyle of the humerus, in which the separated fragment has been displaced upwards.

_Cubitus varus_ is the reverse of cubitus valgus. It is more common, is always pathological, and is nearly always a result of fracture of the lower end of the humerus or separation of the lower humeral epiphysis and subsequent interference with growth. These deformities may be corrected by supra-condylar osteotomy of the humerus.

#Synostosis of the superior radio-ulnar joint# is a rare congenital condition, in which the hinge movements at the elbow are free, but supination is impossible; an attempt may be made by operation to form a new joint.

#Volkmann's ischaemic contracture# of the muscles of the forearm, resulting in the production of claw-hand, is described in Volume I., p. 415.

#Deformities of the Forearm and Hand.#--The _radius_ may be absent completely or in part, frequently in combination with other malformations. The most evident result is a deviation of the hand to the radial side--one variety of _club-hand_. The forearm is shortened, the ulna thickened and often bent, and the thumb and its metacarpal bone are often absent, so that the usefulness of the hand and arm is greatly impaired (Fig. 171). For this condition Bardenheuer devised an operation which consists in splitting the lower end of the ulna longitudinally and inserting the proximal bones of the carpus into the cleft.

Congenital deficiency of the _ulna_ is extremely rare.

#Intra-uterine amputation# by constriction of amniotic bands sometimes occurs (Figs. 168, 169).

#Drop Wrist from Anterior Poliomyelitis.#--In this condition the capacity of extending the fingers is deficient or absent. Recovery can be confidently predicted if, on still further flexing the fingers, they can be voluntarily extended towards the point from which they are flexed (Tubby and Jones). Considerable improvement may result from fixing the hand by means of a splint in the attitude of dorsal flexion. The splint is removed at frequent intervals to allow of massage and other treatment being carried out, and it has usually to be worn for a period of one to two years. In some cases recourse should be had to arthrodesis.

In _spastic paralysis_ the most pronounced deformity is flexion of the forearm and pronation and flexion of the hand (Fig. 166). Gradual extension at the wrist may be brought about by the use of a malleable splint, in which the angle is gradually increased, over a period of at least twelve months. Failing success by this method, operation may be had recourse to, and this consists in lengthening of tendons, and tendon transplantation. Tubby has devised an operation for converting the pronator radii teres into a supinator, and Robert Jones another in which the flexors of the carpus are made to take the place of the extensors. "These operations, combined if necessary with elongation of the flexors of the fingers, pave the way for diminution of the angle of flexion at the elbow, lessening of the pronator spasm, increase of the supinating power, reduction of the carpal flexion, and addition to the extensor power at the wrist" (Tubby and Jones).

#Congenital Club-hand.#--This rare deformity corresponds to congenital club-foot, and probably arises in the same way. The hand and fingers are rigidly flexed to the ulnar or radial side, so that the patient is incapable of moving them. Treatment is carried out on the same lines as for club-foot.

A deformity resembling this, _acquired club-hand_, is brought about when the growth of either of the bones of the forearm has been arrested as a result of disease or of traumatic separation of its lower epiphysis. The hand deviates to the side on which the growth has been arrested--_manus valga_ or _vara_. The treatment consists in resecting a portion of the longer bone.

#Madelung's Deformity of the Wrist.#--In 1878, Madelung called attention to a deformity also called sub-luxation of the hand, in which the lower articular surface of the radius is rotated so that it looks towards the palm; there is palmar displacement of the carpus, and the lower end of the ulna projects on the dorsum. The cause of the condition is obscure, but it is met with chiefly in young women with slack ligaments, whose laborious occupation or athletic pursuits subject the hand and wrist to long-continued or repeated strain. It is as frequently unilateral as bilateral and may recur in successive generations. There is a good deal of pain, the grasping power of the hand is impaired, and dorsiflexion is considerably restricted. The deformity disappears on forcible traction, but at once reappears when the traction is removed. A wristlet of poroplastic or leather extending from the mid-forearm to the knuckles is moulded to the limb in the corrected position, and is taken off at intervals for massage and exercises.

When _operative treatment_ is called for, it takes the form of osteotomy of the radius and ulna about an inch or more above their articular surfaces.

#Congenital dislocation of the wrist# is rare.

#Deformities of the Fingers.#--Various forms of _congenital dislocation_ of the fingers are met with, but they are of little clinical importance, as they interfere but slightly with the usefulness of the digit affected.

_Congenital lateral deviation of the phalanges_ is more unsightly than disabling; it is met with chiefly in the thumb, in which the terminal phalanx deviates to the radial or to the ulnar side in extension; the deviation disappears on flexion.

_Congenital contraction of the fingers_ is comparatively common. It is an inherited deformity, and is often met with in several members of the same family. It most frequently affects the little or the ring and little fingers (Fig. 172), and is usually bilateral. The second and third phalanges are flexed towards the palm; the first phalanx is dorsiflexed, this being the reverse of what is observed in Dupuytren's contraction. Duncan Fitzwilliams suggests that it should be called "hook-finger," and that it is probably due to imperfect development of the anterior ligament of the first inter-phalangeal joint. He has observed it in association with laxity of the ligaments of the other joints of the body.

The affection is usually disregarded in infancy and childhood as being of no importance. In young children, the deformity is corrected by wearing a light splint fixed with strips of plaster, or a piece of whalebone or steel inside the finger of a glove. In older children, the finger may be straightened by subcutaneous division of the ligament over the palmar aspect of the base of the middle phalanx, or failing this by lengthening the flexor tendons and resecting a wedge from the dorsal aspect of the first phalanx close to the inter-phalangeal joint.

#Dupuytren's Contraction.#--This is an acquired deformity resulting from contraction of the palmar fascia and its digital prolongations (Fig. 173). It is rare in childhood and youth, but is common after middle life, especially in men. It is often hereditary, and is said to occur in those who are liable to gout and to arthritis deformans. While it is met with in the working-classes and attributed to the pressure of some hard object on the palm of the hand--such as a hammer or shovel or whip--its greater frequency in those who do no manual work, and the fact that it is very often bilateral, indicate that the constitutional factor is the more important in its causation.

In the initial stage there is a localised induration in the palm opposite the metacarpo-phalangeal joint, and the skin over it is puckered and closely adherent to the underlying fascia. After a variable interval, the finger is gradually and progressively flexed at the metacarpo-phalangeal joint. The ring finger is usually the first to be affected, less often the fifth, although both are commonly involved. It is rarest of all in the index. The flexion may be confined to the metacarpo-phalangeal joint, or the middle and distal phalanges may also be flexed; and as the deformity becomes more pronounced, the nail of the affected finger may come into contact with the skin of the palm. Dissections show that the flexion of the finger is the result of a chronic interstitial overgrowth or fibrositis and subsequent contraction of the palmar fascia and of its prolongations on to the sides of the fingers. The digital processes of the fascia are thickened and shortened, and come to stand out like the string of a bow. The adipose tissue in the skin of the palm disappears, and the skin and fascia thus brought into contact become fused. The tendons and their sheaths are not implicated; they are found lying deeply in the concavity of the curve of the flexed digit. There is no pain, but the grasp of the hand is interfered with, the patient is unable to wear an ordinary glove, and he may be incapacitated from following his occupation.

The condition is easily diagnosed from congenital contraction by the fact that in the latter the proximal phalanx is dorsiflexed.

_Treatment._--When seen in the initial stage, contraction may be prevented by passive movements of the finger and by massage of the indurated fascia; we have observed cases in which these measures have held the malady in check for many years, but when flexion has already occurred, they are useless, and according to the social position, habits, or occupation of the patient, the condition is left alone or the deformity is corrected by operation.

Adam's operation consists in multiple subcutaneous division of the contracted fascia in the palm and of its prolongations on to the finger; in addition to dividing the fascia, the tenotomy knife should be used also to separate the skin from the fascia. The finger is then forcibly extended, and a well-padded splint secured to the hand and forearm. The skin on the palmar aspect opposite the first inter-phalangeal joint may give way when the finger is extended; should this occur, the resulting gap may be covered by a skin graft.

After healing has occurred, massage and movements must be persevered with, and a splint (Fig. 174) worn at night, as there is an inveterate tendency to recurrence of the contraction. In view of this tendency there is much to be said in favour of the radical operation which consists in removal of the fascia by open dissection. Owing to the long time required for healing and the sensitiveness of the scar, the results of excision of the fascia are sometimes disappointing. Greig has obtained good results by resecting the head of the metacarpal bone. When the little finger is completely flexed towards the palm it may be amputated, as it is always in the way.

#Supernumerary Fingers (Polydactylism).#--These may coexist with supernumerary toes, and the condition is often met with in several members of the same family. Sometimes the extra finger is represented by a mere skin appendage, the nature of which may only be indicated by the presence of a rudimentary nail; sometimes it contains bone representing one or more phalanges, or it may be fully formed (Fig. 175). In the majority of cases the superfluous finger should be removed.

#Congenital Deficiencies in the Number of Fingers.#--One or more fingers may be absent, such deficiency being often associated with imperfect development of the radius or ulna; or they may be represented by short rounded stumps, which are ascribed to the strangulation of the digits by amniotic bands _in utero_--the so-called intra-uterine amputation.

#Webbing of Fingers (Syndactylism).#--Congenital webbing or fusion of the fingers may be associated with polydactylism or with congenital hypertrophy, and, like other digital deformities, may affect several members of the same family. The degree of fusion ranges from a web of skin joining the fingers to a fusion of the bones, the latter being well seen in skiagrams. If an operation is decided upon, it should not be performed until the age of five or six years. In the simplest cases it is only necessary to divide the web and to unite the cut edges of skin along each finger by sutures, a skin graft being inserted into the angle between the fingers. An operation in which the skin is dissected up in the form of flaps may be required, but it should not be lightly entered upon, as in young children it has been known to be followed by gangrene of one or more of the digits.

#Congenital Hypertrophy of the Fingers.#--This is a form of local giantism affecting one or more digits, and involving all the tissues. The finger is usually of abnormal size at birth, and continues to grow more rapidly than the others, and it may also come to deviate from its normal axis. Such a finger should be trimmed down or removed, to permit of the use of the other digits.

#Trigger Finger# (Fig. 176).--This is an acquired condition in which movement of a finger or thumb, either in flexion or extension, is arrested, and is only completed with the assistance of the other hand. The obstacle to movement is usually overcome with a jerk or snap suggesting a resemblance to the trigger of a gun or the blade of a clasp-knife. The commonest cause is a disproportion between the size of the tendon and its sheath, such as may result from a localised thickening of the tendon. Recovery usually takes place under massage and passive movements. Failing this, the thickened portion of the tendon is pared down to its normal size; if it is the sheath of the tendon that is narrow, it is laid freely open.

#Drop# or #mallet finger# is described on p. 121.