Chapter X: Deformities of the Extremities (1)

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).

(Photograph taken after death by Dr. Thomson of Norwich.)]

#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.

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

_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.

(Mr. D. M. Greig's case.)]

_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.