Chapter 14

INJURIES IN REGION OF ANKLE AND FOOT

Surgical Anatomy--FRACTURES: _Pott's fracture_; _Converse of Pott's fracture_; _Separation of lower epiphysis_; _Fracture of talus_; _Fracture of calcaneus_; _Fractures of other tarsal bones_; _Fractures of metatarsal bones_; _Fractures of phalanges_--DISLOCATIONS: _Of ankle joint_; _Of inferior tibio-fibular joint_; _Complete dislocation of talus_; _Sub-taloid dislocation_; _Medio-tarsal dislocation_; _Tarso-metatarsal dislocation_; _Dislocations of toes_.

The fractures in this region include Pott's fracture, and its converse; separation of the lower epiphysis of the tibia; fractures of the talus, calcaneus, and other tarsal bones; and fractures of the metatarsals and phalanges. Various dislocations also occur, the most important being those of the ankle joint, of the talus, and the sub-taloid dislocation.

#Surgical Anatomy.#--For the study of injuries in the region of the ankle-joint it is of importance to define the terms employed in describing the movements of the foot. Thus by _flexion_ or _dorsiflexion_ is meant that movement which approximates the dorsum of the foot to the front of the leg; while _extension_ or _plantar flexion_ means the drawing up of the heel so that the toes are pointed. In _inversion_ the medial edge of the foot is drawn up so that the sole looks towards the middle line of the body, an attitude which is analogous to supination of the hand. In _eversion_ the lateral edge of the foot is drawn up, the sole looking away from the middle line--analogous to pronation of the hand. _Adduction_ indicates the rotation of the foot so that the toes are turned towards the middle line of the body; while in _abduction_ the toes are turned away from the middle line.

The most prominent bony landmarks in the region of the ankle are the two _malleoli_, the lateral lying slightly farther back, and about half an inch lower than the medial. On the medial side of the foot from behind forward may be felt the _medial process (internal tuberosity)_ of the calcaneus; the _sustentaculum tali_, which lies about 1 inch vertically below the tip of the malleolus; the _tubercle of the navicular_, about 1 inch in front of the malleolus, and at a slightly lower level; the _first (internal) cuneiform_, and the base, shaft, and head of the _first metatarsal_.

On the lateral side may be recognised the _lateral process (external tuberosity)_ of the calcaneus; the _trochlear process (peroneal tubercle)_ on the same bone; the _cuboid_; and the prominent base of the _fifth metatarsal_.

The talo-navicular joint lies immediately behind the tuberosity of the navicular, and a line drawn straight across the foot at this level passes over the calcaneo-cuboid joint.

The _ankle-joint_, formed by the articulation of the tibia and fibula with the talus, lies about half an inch above the tip of the medial malleolus, and is so constructed that when the foot is at a right angle with the leg it is only possible to flex and extend the joint. When the toes are pointed, however, slight side-to-side and rotatory movements are possible. The chief seat of side-to-side movement of the foot is at the talo-navicular and calcaneo-cuboid articulations--"the mid-tarsal or Chopart's joint."

The ankle-joint owes its strength chiefly to the malleoli and the collateral ligaments, and to the inferior tibio-fibular ligaments, which bind together the lower ends of the bones of the leg. The numerous tendons passing over the joint on every side also add to its stability.

The synovial membrane of the ankle-joint passes up between the bones of the leg to line the inferior tibio-fibular joint; but it is distinct from that of the intertarsal joints, which communicate with one another in a complicated manner. The epiphysial cartilage at the lower end of the fibula lies on the level of the talo-tibial articulation, while that of the tibia is about half an inch higher (Fig. 93).

FRACTURES IN THE REGION OF THE ANKLE

#Pott's Fracture.#--It must be understood that various lesions occurring in the region of the ankle-joint are included under the clinical term "Pott's fracture." Although of a similar nature, and produced by the same forms of violence, these vary considerably in their anatomy and clinical features. They are all the result of _combined eversion and abduction_ of the foot--produced, for example, by slipping off the kerbstone, or by jumping from a height and landing on the medial side of the foot.

When forcible _eversion_ is the chief movement, the tightening of the deltoid (internal lateral) ligament usually tears off the medial malleolus across its base. The talus is then brought to bear on the lateral malleolus, and the force continuing to act, the lower end of the fibula is pressed laterally, and breaks close above the malleolus. The tibio-fibular interosseous ligament may rupture, or the outer portion of the tibia, to which it is attached, may be avulsed. This form is sometimes called _Dupuytren's fracture_. When the bones are widely separated in Dupuytren's fracture the talus may be forced up between them.

When the movement of _abduction_ predominates, the deltoid ligament is usually ruptured, or the anterior edge or tip of the medial malleolus torn off. The tibio-fibular interosseous ligament usually resists, and an oblique fracture of the fibula 2 or 4 inches above its lower end results.

_Clinical Features._--In a considerable proportion of cases--in our experience in the majority--this fracture is not accompanied by any marked deformity of the foot, and the patient is often able to walk after the injury with only a slight limp.

In others, however, the deformity is marked and characteristic (Fig. 94). The foot is everted, its inner side resting on the ground. The medial malleolus is unduly prominent, stretching the skin, which may give way if the patient attempts to walk. The foot, having lost the support of the malleoli, is often displaced backward, and the toes are pointed by the contraction of the calf muscles. There is abnormal mobility--both from side to side and antero-posteriorly--and crepitus may be elicited. The points of tenderness are over the deltoid ligament or medial malleolus, the inferior tibio-fibular joint, and at the seat of fracture of the fibula. Distal pressure over the shaft of the fibula, or on the extreme tip of the malleolus, may elicit pain and crepitus at the seat of fracture. There is usually considerable ecchymosis and swelling in the hollows below and behind the malleoli; and the malleoli appear to be nearer the level of the sole. In Dupuytren's fracture, when the talus passes up between the tibia and fibula, there is great broadening of the ankle.

There is often considerable difficulty in distinguishing a _sprain_ of the ankle from a fracture without displacement, as both forms of injury result from the same kinds of violence, and are rapidly followed by swelling and discoloration of the overlying soft parts. In a sprain, the point of maximum tenderness is over the ligaments and tendon sheaths that have been damaged, while in fracture the site of the break is the most tender spot. The X-rays are useful in the diagnosis of doubtful cases.

_Treatment._--In those cases of fracture of the lower end of the fibula in which there is no marked displacement,--and they constitute a considerable proportion,--the limb should be massaged and laid on a pillow between sand-bags, or placed in a box splint for two or three days, until the swelling subsides. Some form of rigid apparatus, such as side poroplastic splints fixed in position with an elastic bandage, which will allow the patient to get about with crutches, is then applied. This is removed daily to permit of massage and movement being carried out--a point of great practical importance, because, if this is neglected, not only does union take place more slowly, but the stiffness of the ankle and oedema of the leg and foot which ensue, prolong the period of the patient's incapacity and endanger the usefulness of the limb.

It is in cases of this kind that the _ambulatory method_ of treatment yields its best results. When, in the course of two or three days, the swelling has subsided, a plaster-of-Paris case (Fig. 95) is applied in such a way that when the patient walks the weight is transmitted from the condyles of the tibia through the plaster case to the ground, no weight being borne by the bones at the seat of fracture. The apparatus is applied as follows: A boracic lint bandage is applied to the limb as far as the knee, and protecting pads or rings of wool are placed over the condyles of the tibia, the head of the fibula, and the malleoli. A pad of wool about 3 inches thick is then placed under the sole and fixed in position by a plaster-of-Paris bandage, which is carried up the limb in the usual way. The case is made specially strong on the sole, around the ankle, up the sides of the leg, and at the bearing-point at the head of the tibia. After the plaster has thoroughly set, the patient is allowed to walk about with a stick, crutches being unnecessary. In the course of three weeks the plaster case may be removed and the limb massaged. It is usually found that the movements of the ankle are scarcely interfered with, and the patient is generally able to resume work within a month of the accident.

When there is marked eversion of the foot, it may be necessary to administer a general anaesthetic to reduce the deformity; and to prevent recurrence of the displacement _Dupuytren's splint_ (Fig. 96) may be used. This splint, which is of the same shape as Liston's long splint, but on a small scale, is applied to the medial side of the leg extending from just below the knee to well beyond the sole of the foot. A large pad is placed in the hollow above the medial malleolus, and it must be thick enough to carry the splint so far from the limb that when the foot is fully inverted it does not touch the splint. The upper end of the splint having been fixed to the leg at the level of the condyles of the tibia, a bandage is applied to correct the eversion of the foot, and at the same time to support the heel, and, as far as possible, to overcome the pointing of the toes. Care must be taken to avoid carrying the turns of this bandage over the seat of fracture. The limb may then be slung in a cradle, or placed on a pillow resting on its lateral side with the knee flexed. In the course of a few days, a poroplastic splint may be substituted and massage commenced.

When backward displacement of the heel is the prominent deformity, _Syme's horse-shoe_ or _stirrup splint_ (Fig. 97) may be employed. It is applied to the anterior aspect of the limb, which is carefully padded to prevent undue pressure on the edge of the shin bone. After the upper end of the splint has been fixed, the heel is pulled forward by a few turns of bandage passed over the prongs at the lower end of the splint. The foot is then inverted and brought up to a right angle by a few supplementary turns of the bandage. In a few days this appliance may be replaced by a poroplastic splint.

_Operative Treatment._--If the displacement is not completely corrected by the measures described, the fibular fracture is exposed by a free incision and the fragments are levered into position, and if necessary fixed by lashing with catgut or by other mechanical means.

Mal-union of Pott's fracture may necessitate re-fracture by means of a Jones' wrench, used in the same manner as for club-foot, or the parts are exposed by operation; the bone is divided by means of an osteotome, the foot forcibly inverted, and the limb put up in the same way as in a recent fracture.

#The Converse of Pott's Fracture--sometimes called "Pott's Fracture with Inversion."#--This injury is fairly common, and results from forcible inversion of the foot. The lateral malleolus is broken across its base, or, in young subjects, along the epiphysial line. The medial malleolus alone may be carried away, or a portion of the broad part of the tibia may accompany it.

The foot is inverted, the heel falls back, and the toes are pointed. In other respects it corresponds to the typical Pott's fracture, and is treated on the same principles. When Dupuytren's splint is required, it is, of course, applied to the lateral side of the leg.

#Separation of the lower epiphysis of the tibia# is not common. It occurs most frequently between the ages of eleven and eighteen, as a result of forcible eversion or inversion of the foot. It is usually accompanied by fracture of the diaphysis of the fibula (Fig. 98), and is not infrequently compound. When the epiphysis is displaced to one side, the deformity is characteristic. In rare cases the growth of the tibia is arrested, the continued growth of the fibula causing the foot to become inverted. The treatment is the same as for Pott's fracture.

#Fracture of the talus# usually occurs as a result of a fall from a height, the bone being crushed between the tibia and the calcaneus. It is usually associated with other fractures, and is sometimes impacted, the foot assuming the position of equino-varus. The diagnosis is only to be made by exclusion, or by the use of the Roentgen rays. In interpreting radiograms of injuries in this region, care must be taken not to mistake the _os trigonum tarsi_ for a fracture. In uncomplicated cases, the treatment consists in immobilising the foot and leg in a poroplastic splint and applying massage. In comminuted and in impacted fractures with persistent deformity, complete excision of the bone yields good results.

The #calcaneus# is most frequently broken by the patient falling from a height and landing on the sole of the foot, and the injury may occur simultaneously in both feet.

The primary fracture is usually longitudinal, passing through the facets for the talus and cuboid, and from this various secondary fissures radiate; the cancellated tissue is much crushed, so that the whole bone is flattened out. In spite of the great comminution, it is often impossible to elicit crepitus, as the fragments are held together by the investing soft parts. In other cases the foot may feel like "a bag of bones." The lesion is often mistaken for a fracture of the lower end of the fibula, or is not diagnosed at all. The chief clinical feature is pain on movement of the foot, or on attempting to walk; the foot appears flat, and the hollows on either side of the tendo Achillis are filled up. In many cases there is a persistent tenderness which delays restoration of function for some months, but the ultimate result is usually satisfactory.

_Treatment._--In simple comminuted fractures the patient should be anaesthetised, and the foot moulded into position, care being taken to restore the arch in order to avoid any tendency to flat foot. The foot is supported on a pillow, and to prevent stiffness, massage and movements of the ankle and tarsal joints should be commenced without delay.

Compound fractures confined to the calcaneus may be treated on conservative lines, but if associated with other injuries of the foot they may necessitate amputation.

_The tuberosity of the calcaneus_, into which the tendo Achillis is inserted, is sometimes separated by forcible contraction of the calf muscles, or from a fall on the ball of the foot. The separated fragment may be pulled up for a distance of 1 or 2 inches, and the rough surface from which it has been torn may be recognisable. The patient may be able to walk immediately after the accident, although with difficulty; or he may have pain for many months.

A good functional result is usually obtained by relaxing the calf muscles and fixing the foot in the position of extreme plantar flexion with the knee flexed, but in some cases it is advisable to peg the fragments, either through the skin or after exposing them by operation.

The #other bones of the tarsus# are rarely fractured separately. The _tuberosity of the navicular_ is sometimes torn away by violent traction on the ligaments attached to it.

#Fractures of the metatarsals and phalanges# usually result from direct violence, such as a crush of the foot, in which the soft parts are severely damaged. The use of the Roentgen rays has shown, however, that certain painful conditions in the foot following comparatively slight injuries, such as kicking a stone, are due to a fracture of one of the metatarsals or phalanges.

When simple, these injuries are often overlooked, on account of the difficulty of eliciting the signs of fracture from the swelling which accompanies them. They are best treated in a moulded splint.

Compound fractures are more common, and are to be treated on the same principles as govern such injuries elsewhere.

_A fracture of the base of the fifth metatarsal_ has been described by Sir Robert Jones. It is produced by the patient coming down forcibly on the lateral edge of the foot while the foot is inverted and the heel raised--as, for example, in dancing. There is a localised swelling over the base of the fifth metatarsal, and pain when the patient puts weight on the foot. There is no crepitus or deformity. The fracture is readily recognised by the Roentgen rays. Massage and movement are employed from the first.

DISLOCATIONS IN THE REGION OF THE ANKLE

#Dislocation of the Ankle-Joint.#--In describing dislocation of the talus from the tibio-fibular socket, the varieties are named according to the direction in which the foot passes--backward, forward, medially, laterally, or upward.

All of them may be complete, but they are more frequently incomplete, and are liable to be rendered compound, either from tearing of the skin at the time of the injury, or by its sloughing later. Although as a rule there is little difficulty in effecting reduction by manipulation, these injuries are liable to be followed by stiffness and impaired usefulness of the joint.

The _backward_ dislocation is the most common, and results from extreme plantar flexion of the foot, as from a fall backwards while the foot is fixed, wedging the talus between the tibia and fibula. The collateral ligaments are torn, and one or both malleoli may be broken, or the posterior part of the articular edge of the tibia chipped off (Fig. 99).

The foot appears shortened, the heel is unduly prominent behind, and the lower ends of the tibia and fibula project in front, sometimes coming through the skin. The tendons around the joint are stretched or torn.

_Forward_ dislocation results from extreme dorsal flexion at the ankle-joint. The foot appears lengthened, the heel is less prominent than normal, and the hollows on each side of the tendo Achillis are obliterated. The talus is felt in front of the tibia, and the malleoli appear to be displaced backwards and to lie nearer the sole.

_Medial_ or _lateral_ dislocation is only possible after fracture of one or both malleoli, and may be looked upon as a complication of these injuries.

In cases in which the interosseous ligament is ruptured, and in severe cases of Dupuytren's fracture, the talus may be driven _upwards_ between the bones of the leg. There is great broadening in the region of the ankle, and the malleoli are unduly prominent under the skin, which is tightly stretched over them. They are also nearer to the sole than normally. The movements of the ankle-joint are lost.

Dislocation of the _inferior tibio-fibular joint_ is exceedingly rare, except in association with fractures of the lower ends of the bones of the leg, particularly Dupuytren's fracture, or with dislocation of the ankle-joint proper.

_Treatment of Dislocation of Ankle._--The patient having been anaesthetised, the foot is extended and the knee and hip joints flexed to relax the calf muscles as completely as possible. Traction is then made upon the foot, while counter-extension is applied to the leg, and the bones are manipulated into position. Reduction usually takes place gradually without the characteristic snap which accompanies reduction of most dislocations. It is sometimes necessary to divide the tendo Achillis, particularly in cases of forward dislocation.

When the talus passes upwards between the tibia and fibula, it is sometimes impossible to effect reduction by manipulation, and the best results are then obtained by operation.

The after-treatment consists in keeping the leg on a pillow between sand-bags, and carrying out the usual massage and movement.

In compound dislocations which have become infected, primary amputation may be indicated, but in young and healthy subjects an attempt may be made to save the foot.

#Dislocation of the talus# from its articulations with the bones of the leg above and the calcaneus and navicular below, is a comparatively common injury, and results from a violent wrench of the foot. It may be incomplete or complete. When the foot is plantar flexed at the moment of injury, the displacement is generally _forward_ with a tendency outward. The talus comes to rest on the third cuneiform and cuboid bones, the foot being abducted, inverted, and displaced medially. In a large proportion of cases the dislocation is compound, more or less of the talus being forced through the skin (Fig. 100).

When the foot is dorsiflexed at the moment of injury the displacement is _backward_, but this is rare, as is also _dislocation to one or other side_, and _dislocation by rotation_, in which the talus is rotated in its socket. In all these injuries the body of the talus loses its normal relationship with the malleoli.

An attempt should be made to reduce the dislocation under anaesthesia, the limb being placed in the same position as for reduction of dislocation of the ankle. While traction is made upon the foot, an assistant presses directly on the displaced bone and endeavours to manipulate it into position. In incomplete dislocations this usually succeeds, but it not infrequently fails in those which are complete, and under these circumstances it may be necessary to chisel through the lateral malleolus to admit of reduction, or to excise the talus. In most cases of compound dislocation also, this bone should be removed.

#Sub-taloid Dislocation.#--In this dislocation, which results from the same kinds of violence as the last, the talus retains its position in the tibio-fibular socket, and the calcaneus and navicular, with the rest of the foot, are carried away from it. The body of the talus, therefore, maintains its normal relationship with the malleoli--a point of importance in the differential diagnosis between this injury and dislocation of the talus. The displacement is usually incomplete, and the foot may either pass backward and medially, or backward and laterally. When the foot passes _backward and medially_, the head of the talus projects on the outer part of the dorsum, resting on the cuboid. The dorsum of the foot is shortened, the heel lengthened, the toes adducted, and the medial border of the foot raised. The lateral malleolus is unduly prominent, and reaches nearly to the sole.

In the _backward and lateral_ variety, the medial malleolus and head of the talus project unduly towards the medial side of the foot, which is abducted and everted.

In neither variety is there any mechanical obstacle to movement at the ankle-joint.

The _treatment_ is carried out on the same lines as for dislocation of the talus, reduction being effected without difficulty in most cases. If this fails, as it occasionally does, it may be necessary to excise the talus.

#Mid-tarsal or transverse tarsal dislocation#--that is, at the talo-navicular and calcaneo-cuboid articulations--is extremely rare. The distal segment of the foot is usually displaced towards the sole; the foot is foreshortened, the malleoli raised from the sole, the arch of the foot is lost, and the first row of tarsal bones projects on the dorsum. The treatment consists in reducing the displacement by manipulation, after which massage and movement are employed.

#Tarso-metatarsal Dislocations.#--One, several, or all of the metatarsals may be separated from the distal row of tarsal bones--the usual cause being a fall from a horse, the foot being fixed in the stirrup. The bases of the metatarsal bones are displaced laterally and towards the dorsum. The base of the second metatarsal and the first cuneiform are sometimes fractured. Reduction by manipulation is generally easy in dorsal dislocations, but may be difficult when the bones are displaced laterally. This may be due to fragments of bone or soft parts getting between the bones, and may necessitate operative interference. In old-standing dislocations, operation is to be advised only when locomotion is seriously interfered with.

#Dislocation of the Toes.#--The great toe may be dislocated at its metatarso-phalangeal joint, the base of the proximal phalanx passing towards the dorsum (Fig. 102). Diagnosis and reduction are alike easy.

#Inter-phalangeal# dislocations are rare and are easily reduced.