CHAPTER VII

INJURIES IN THE REGION OF THE KNEE AND LEG

_Surgical Anatomy_--FRACTURE OF LOWER END OF FEMUR: _Supra-condylar_; _T- or Y-shaped_; _Separation of epiphysis_; _Either condyle_--FRACTURE OF UPPER END OF TIBIA: _Of head_; _Separation of epiphysis_; _Avulsion of tubercle_--DISLOCATIONS OF KNEE: _Dislocations of superior tibio-fibular joint_--INTERNAL DERANGEMENTS OF KNEE--INJURIES OF PATELLA: _Fractures_; _Dislocations_--INJURIES OF LEG: _Fracture of both bones_; _Fracture of tibia alone_; _Fracture of fibula alone_.

INJURIES IN THE REGION OF THE KNEE

These include the supra-condylar fracture of the femur, the T- or Y-shaped fracture opening into the joint, separation of the lower femoral epiphysis; fracture of the head of the tibia, and separation of its upper epiphysis; the various sprains and dislocations of the knee, as well as its internal derangements; and fractures and dislocations of the patella.

#Surgical Anatomy.#--Of the two epicondyles the medial is the more prominent and palpable. The adductor tubercle, which is situated on the upper and back part of the medial epicondyle, gives attachment to the round tendon of the adductor magnus, and marks the level of the epiphysial line and of the upper limit of the trochlear surface of the femur. Between the medial condyle of the femur and the medial condyle (tuberosity) of the tibia, when the limb is in the flexed position, the line of the joint can be recognised as a groove or cleft, and this is made use of in measuring the length of the tibia. The lateral condyle (tuberosity) of the tibia can also be palpated, and must not be mistaken for the head of the fibula, which lies farther back and at a slightly lower level, and can readily be identified by tracing to it the tendon of the biceps. The tuberosity of the tibia, into which the quadriceps extensor tendon is inserted, lies on the same level as the head of the fibula. In the extended position of the limb, the patella is loose and movable on the front of the trochlear surface of the femur, while in the flexed position it sinks between the condyles, resting chiefly on the lateral one and becoming fixed.

The popliteal artery and vein and the tibial (internal popliteal) nerve lie in close relation to the posterior aspect of the joint; and the common peroneal (external popliteal) nerve passes behind and to the medial side of the biceps tendon.

The knee is an example of a joint which depends for its strength chiefly on its ligaments. Not only are the tibial and fibular collateral (external and internal lateral) ligaments and the posterior part of the capsular ligament particularly strong, but the cruciate ligaments and the menisci (semilunar cartilages) inside the cavity of the joint further add to its stability. The powerful tendon of the quadriceps extensor muscle, in which the patella is developed as a sesamoid bone, protects and strengthens the front of the joint and functionates as the anterior ligament of the joint. In the attitude of complete extension in which the joint is locked, no demand is made on the quadriceps apparatus; with the commencement of flexion, the stability of the joint, and the weight-bearing capacity of the limb as a whole, depend largely on the controlling influence of the quadriceps muscle; this becomes evident on going down an incline and more markedly on going down stairs. Hence it is, that in recurrent sprains of the knee, including under this term the various forms of internal derangement of the joint, the wasting with loss of tone of the quadriceps is an important factor in aggravating the disability of the limb and in retarding and preventing recovery. In the treatment of recurrent sprains of the knee, therefore, special attention must be directed towards the wasting of the quadriceps by means of massage and appropriate exercises.

The synovial cavity extends from the level of the head of the tibia to an inch or more above the trochlear surface of the femur, passing slightly higher on the medial aspect of the joint than on the lateral (Fig. 80). The large bursa between the quadriceps muscle and the femur (_sub-crural bursa_) generally communicates with the cavity of the joint. The synovial cavity of the superior tibio-fibular articulation is usually distinct from that of the knee-joint, but may communicate with it through the popliteal bursa.

A large bursa (_pre-patellar_) lies over the lower part of the patella and upper part of the ligamentum patellae; and a smaller one separates the ligamentum patellae from the tuberosity of the tibia. Several important bursae are found in the popliteal space, one of which--the semi-membranosus bursa--sometimes communicates with the knee-joint.

FRACTURE OF THE LOWER END OF THE FEMUR

Fractures involving the lower end of the femur, especially the supra-condylar and T-shaped fractures, are to be looked upon as serious injuries, on account of the difficulties attending their treatment, and the risk of damage to the popliteal vessels and of impairment of the usefulness of the knee-joint.

#Supra-condylar# fracture is usually the result of a fall on the feet or knees, or of direct violence, and is most common in adult males. The line of fracture is generally irregularly transverse, or it may be slightly oblique from above downwards and forwards, so that the proximal fragment passes forward towards the patella, while the distal is rotated backward on its transverse axis by the gastrocnemius muscle.

_Clinical features._--Soon after the accident a copious effusion of blood and synovia takes place into the cavity of the knee-joint, adding to the swelling caused by the displaced bones, and rendering it difficult to recognise the precise nature of the lesion. As it is important to make an accurate diagnosis, the X-rays should be employed if possible, and a general anaesthetic should be given when necessary.

The proximal end of the distal fragment is usually palpable in the popliteal space, while the proximal fragment is unduly prominent in front. By flexing the knee the fragments may be brought into apposition and crepitus elicited. In oblique fractures, the pointed lower end of the proximal fragment may transfix the quadriceps extensor muscle and may be felt under the skin, or it may perforate the skin and thus render the fracture compound. It should be disengaged by fully flexing and making traction on the knee. The thigh is shortened to the extent of from 1/2 to 1 inch.

The popliteal vessels lie so close to the bone that they are liable to be torn by the displaced distal fragment, giving rise to the usual signs of ruptured artery. Sometimes, owing to the feeble state of the circulation from shock, the bleeding does not take place at the time of the accident, but ensues some hours later. The vessels may merely be pressed upon by the displaced bone, but the nutrition of the limb beyond is endangered and gangrene may ensue if early reduction be not effected.

_Treatment._--The small size of the distal fragment, its depth from the surface, and the accompanying effusion into and around the joint, render its control difficult. In the majority of cases the two fragments can only be brought into apposition when the knee is flexed on the thigh and the thigh on the pelvis, and it is almost always necessary to carry out the reduction under anaesthesia.

In the few cases in which the fragments can be accurately approximated in the extended position of the limb, retention may be effected by means of a box splint reaching well up the thigh (p. 180).

In the majority, however, flexion is necessary, and a Thomas' knee splint with flexion attachment bent to an angle of 30 deg. (Fig. 81) and extension by means of ice-tong callipers secures the best apposition. If this apparatus is not available the limb must be fixed on a double-inclined plane, so constructed that the angle of flexion can be adjusted to meet the requirements of the individual case (Fig. 70).

Hodgen's splint, bent nearly to a right angle, may also be employed.

A careful watch must be kept on the circulation of the limb during the first few days, lest it be interfered with by the pressure of the apparatus.

In a considerable number of cases these means of retaining the fragments in apposition prove ineffectual, and it is necessary to have recourse to operative measures for mechanical fixation. Division of the tendo calcaneus (Achillis) is not to be recommended as a means of combating the backward tilting of the distal fragment.

In all cases the retentive apparatus must be worn for about four weeks, after which the limb is flexed over a pillow; but massage and movement should be employed as soon as possible, as persistent stiffness of the knee is one of the most troublesome sequelae of these injuries.

Compound and complicated fractures are dealt with on the general principles governing the treatment of such injuries. Amputation may become necessary should gangrene ensue from injury to the popliteal vessels, or if infective complications threaten the life of the patient.

Operative interference may be called for to rectify deformities resulting from mal-union.

The #T- or Y-shaped fracture# is, as a rule, produced by direct violence, the force first breaking the bone above the condyles and then causing the proximal fragment to penetrate the distal and split it up into two or more pieces. The fracture implicates the articular surface, and the main fissure is usually through the inter-condylar notch; the lower end of the bone is sometimes severely comminuted.

The knee is broadened, and pain and crepitus are readily elicited on moving the condyles upon one another or on pressing them together. On moving the patella transversely, it may be felt to hitch against the edge of one or other of the fragments. The shortening may amount to one or two inches.

The treatment is carried out on the same lines as in supra-condylar fracture, but as the joint is implicated there is greater risk of subsequent impairment of its functions.

#Separation of the lower epiphysis# is a comparatively common injury. It is seldom pure, a portion of the diaphysis usually being broken off and remaining attached to the epiphysis. It occurs usually in boys between the ages of thirteen and eighteen, from severe violence such as results from the limb being caught between the spokes of a revolving wheel, or from hyper-extension of the knee. It has also been produced in attempting forcibly to rectify knock-knee and other deformities in this region, and in making traction on the limb to correct deformities following recovery from tuberculous disease of the knee. As a rule, there is little displacement of the loose epiphysis, but it may pass in any direction, forward being much the most common (Fig. 82), and when displaced it is difficult to reduce and to maintain in position. The age of the patient, the mode of injury, the finding of the smooth broad end of the diaphysis in the popliteal space or on the front of the thigh, according to the displacement, usually serve to establish the diagnosis. The X-rays afford reliable information as to the position of the fragments. Pressure on the popliteal vessels is a serious aggravation of the injury, and adds greatly to the difficulties of treatment.

The treatment is the same as for supra-condylar fracture, but, owing to the serious disability that follows on incomplete reduction, it may be necessary to have recourse to operation. After an epiphysial separation, the growth of the limb is sometimes, although not always, interfered with.

#Either condyle# may be broken off without the continuity of the shaft being interrupted, by a direct blow or fall on the knee, or by violent twisting of the leg. The separated condyle may not be displaced, or it may be pushed upwards or rotated on its transverse axis.

There is broadening of the knee but no shortening of the thigh, and the ecchymosis, crepitus, and pain are localised to the affected side of the joint; the knee can usually be moved towards the injured side in a way that is characteristic. If allowed to unite with the condyle displaced, the articular surface is oblique and bow- or knock-knee results.

If there is difficulty in replacing the broken condyle and maintaining it in position, it may be fixed by means of a steel nail inserted through the skin.

FRACTURE OF THE UPPER END OF THE TIBIA

#Fracture of the head of the tibia# is a comparatively rare injury. It may result from a direct blow, such as the kick of a horse, or from indirect forms of violence, and the line of fracture may be transverse or oblique. Occasionally the distal fragment is impacted into the proximal and comminutes it. In oblique fracture a gliding displacement is liable to occur and cause bow- or knock-knee. Transverse fracture of the head of the fibula sometimes accompanies fracture of the head of the tibia, and there is always considerable effusion into the knee-joint. One or other of the condyles may be chipped off by forcible adduction or abduction at the knee.

The ordinary clinical features of fracture are well marked, and the diagnosis is easy. From some unexplained cause this fracture may take a long time, sometimes several months, to consolidate.

#Separation of the upper epiphysis# of the tibia, which includes the tongue-like process for the tubercle and the facet for the fibula, is also rare. It usually occurs between the ages of three and nine. The displacement of the epiphysis is almost always forward or lateral, and is accompanied by the usual signs of such lesions. The growth of the limb is sometimes arrested, and shortening and angular deformity may result.

_Treatment._--After reduction under an anaesthetic these fractures are usually satisfactorily treated in a box splint (Fig. 91), carried sufficiently high to control the knee-joint. When the head of the tibia is comminuted or split obliquely, weight-extension--direct from the bone, the ice-tong callipers grasping the malleoli or the calcaneus--may be used. Massage and movement are employed from the outset.

Avulsion of the #tuberosity of the tibia# occasionally occurs in youths, from violent contraction of the quadriceps--as in jumping. The limb is at once rendered powerless; the osseous nodule can be felt, and on moving it crepitus is elicited.

This is best treated by pegging the tuberosity in position, and fixing the extended limb on an inclined plane to relax the quadriceps muscle.

In young, athletic subjects, the tongue-like process of the epiphysis (Fig. 85), into which the ligamentum patellae is inserted, may be partly or completely torn away, giving rise to localised swelling, and pain which is aggravated by any muscular effort--_Schlatter's disease_ or "rugby knee." It has been frequently observed in cadets as a result of kneeling at drill. The treatment consists in rest and massage, but the symptoms are slow to disappear.

The condition is liable to be mistaken for some chronic inflammatory condition of the bone, such as tubercle, unless an X-ray examination is made.

The #upper end of the fibula# is seldom broken alone. The chief clinical interest of this fracture lies in the fact that it may implicate the common peroneal nerve, and cause drop-foot.

DISLOCATIONS OF THE KNEE

Dislocation of the knee is a rare injury, and occurs as a result of extreme degrees of violence, especially of a wrenching or twisting character.

Rupture of the popliteal vessels, or pressure exerted on them by the displaced bones, may lead to gangrene of the limb, and necessitate amputation. The common peroneal nerve is frequently damaged. When the lesion is compound, also, amputation may become necessary on account of infective complications.

The varieties of dislocation are named in terms of the direction in which the tibia passes: forward, backward, medial, and lateral.

#Dislocation forward# is the most common variety, and results from sudden hyper-extension of the knee, tearing the collateral and cruciate ligaments. The leg remains fully extended, and lies on a plane anterior to that of the thigh. The condyles of the femur are palpable posteriorly, and the skin is tightly stretched over them, or may even be torn, rendering the dislocation compound. The patella is projected forward, the quadriceps tendon is lax, and the skin over it is thrown into transverse folds. The limb is shortened by two or three inches.

#Dislocation backward# is usually due to a direct blow driving one of the bones past the other. The leg remains hyper-extended, the head of the tibia occupies the popliteal space, while the lower end of the femur projects forward with the patella either in front or to one side of it.

The #medial and lateral dislocations# are generally incomplete, and are liable to be mistaken for separation of the lower epiphysis of the femur. When the tibia passes _medially_, the lateral condyle of the femur forms a prominence, and there is a depression below it. The head of the tibia projects on the medial side, and the medial condyle is in a depression.

When the tibia is displaced _laterally_, the relative position of the prominences and depressions is reversed.

_Treatment._--In dislocations of the knee no special manipulations are necessary to restore the displaced bone to its place, and reduction is not accompanied by a distinct snap.

If, while the patient is fully anaesthetised, traction is made on the leg and counter-traction on the thigh with the knee in the flexed position, the bones can usually be replaced by manipulation.

After reduction has been effected, in antero-posterior dislocations, the limb should be flexed and placed on a pillow, massage and movement being employed from the first. The patient is usually able to walk within a month.

In medial and lateral dislocations there is at first considerable tendency to re-displacement, and it is therefore necessary to secure the joint in a box splint, specially padded, for about fourteen days, massage being employed from the first, and movement commenced when the splint is removed. It is usually about six weeks before the patient can use the limb with freedom.

In compound dislocations, and in those complicated by injury to the popliteal vessels, the question of amputation may have to be considered.

#Dislocation of the Superior Tibio-Fibular Articulation.#--This joint may be dislocated by twisting forms of violence applied to the foot or leg, or by forcible contraction of the biceps muscle. The displacement may be forward or backward, and the head of the fibula can be felt in its new position with the prominent tendon of the biceps attached to it. The movements of the knee are quite free, but the patient is unable to walk on account of pain. Reduction and retention are, as a rule, easy, and the ultimate result satisfactory. We have frequently met with this injury accompanying compound fractures of both bones of the leg resulting from railway and similar accidents.

By applying direct pressure over the displaced bone with the knee flexed, the dislocation is easily reduced. It is kept in position by a firm bandage or a light rigid splint.

#Total Dislocation of Fibula.#--Very rarely the fibula is separated from the tibia at both ends and displaced upwards. Bennett of Dublin has pointed out that in some persons the upper end of the fibula does not reach the facet on the tibia--a condition which might be mistaken for a dislocation.

INJURIES OF THE SEMILUNAR MENISCI

The semilunar menisci are two crescentic plates of white fibro-cartilage, which lie upon the upper end of the tibia, and serve to deepen the articular surface for the condyles of the femur. Each cartilage is firmly attached to the tibia by its anterior and posterior ends, and, through the medium of the coronary ligaments, is loosely attached along its peripheral, convex edge to the head of the tibia, the medial meniscus being connected also to the capsular ligament of the joint. The tendon of the popliteus muscle intervenes between the lateral meniscus and the capsule. The central, concave edges of the menisci are thin and unattached.

The cartilages enjoy a limited range of movement within the joint, passing backwards during flexion, and forwards again when the limb is extended; under normal conditions the lateral moves more freely than the medial. While the limb is partly flexed, a slight degree of rotation of the leg at the knee is possible, and during this movement the cartilages glide from side to side, and the tibia rotates below them.

Any abnormal laxity of the ligaments of the joint may render the cartilages unduly mobile, so that they are liable to be displaced from comparatively slight causes, and when so displaced it is not uncommon for one or other to be torn by being nipped between the femur and the tibia. It is convenient to consider these "internal derangements of the knee-joint" separately, according to whether the meniscus is merely abnormally mobile, or is actually torn.

#Mobile Meniscus--Displacement of Medial Semilunar Cartilage# (Fig. 86).--The _medial_ meniscus exhibits undue mobility much more frequently than the lateral, and the condition is usually met with in adult males who engage in athletics, or who follow an employment which entails working in a kneeling or squatting position for long periods, with the toes turned outwards--for example, coal-miners. The tibial collateral ligament, and through it the coronary ligament, are thus gradually stretched, so that the cartilage becomes less securely anchored, and is rendered liable to be displaced towards the centre of the joint during some sudden movement which combines flexion of the knee with medial rotation of the femur upon the tibia, as, for example, in rising quickly from a squatting position, or turning rapidly and pushing off with the foot, in the course of some game such as football or tennis. It may occur also from tripping on a loose stone or slipping off the kerbstone.

What actually happens when the meniscus is displaced would appear to be, that the combined flexion and abduction of the knee opens up the medial side of the joint by separating the medial condyles of the femur and tibia, and that the medial meniscus in its movement backward during flexion slips under the femoral condyle and is caught between it and the tibia. It may even slip past the condyle and into the intercondyloid notch, and come to lie against the cruciate ligaments.

The mechanism by which this lesion is produced doubtless explains the greater frequency with which the _left_ knee is affected, as most sudden movements are made from right to left, thus throwing the strain upon the left knee.

_Clinical Features._--When seen immediately after the accident, the patient usually gives the history that while making a sudden movement he was seized with an intense sickening pain in the knee, accompanied, it may be, by a sensation of something giving way with a distinct crack, and followed by locking of the joint. He may fall to the ground and be unable to rise. On examination, the knee is found to be fixed in a slightly flexed position; and while the surgeon may be able to carry out movements of flexion to a considerable extent without increasing the pain, any attempt to extend the joint completely is extremely painful. Tenderness may be elicited on making pressure to the medial side of the ligamentum patellae in the groove between the femur and the tibia, but the meniscus cannot be recognised by palpation. Considerable effusion rapidly takes place into the synovial cavity.

The condition is liable to be mistaken for a sprain of the joint, particularly one implicating the tibial collateral ligament, but whereas in the lesion of the meniscus the maximum tenderness is in the interval _between_ the bones, in the sprain of the ligament the maximum tenderness is over its attachment to the bone, usually the tuberosity of the tibia.

_Treatment._--To reduce the displacement, the patient is placed on a couch, and, after the knee is fully flexed, the leg is rotated laterally and abducted, to separate the medial femoral condyle from the tibia, and while the rotation and abduction are maintained the leg is quickly extended. The return of the meniscus to its place is sometimes attended with a distinct snap, but in other cases reduction is only recognised to have taken place by the fact that the joint can be completely extended without causing pain.

Alternate flexion and extension combined with rotatory movements is sometimes successful. Several attempts are often necessary, and a general anaesthetic may be called for. After reduction, the limb is fixed with sand-bags, and massage and movement are employed to get rid of effusion, care being taken that no rotatory movement at the knee is permitted. Rest and support are necessary to allow of repair of the torn ligaments, and when the patient begins to use the limb he must be careful to avoid movements which throw strain on the damaged ligaments.

In a considerable proportion of cases no recurrence takes place, and in the course of a month or two the patient is able to resume an active life with a perfectly useful joint. In other cases there is a tendency to recurrence of the displacement.

#Recurrent Displacement.#--In cases of recurrent displacement, each attack is accompanied by symptoms similar in kind to those above described, but less severe, and the patient usually learns to carry out some manipulation by which he is able to return the meniscus into position. He seeks advice with a view to having something done to prevent displacement occurring, and to restore the stability of the joint, which, in many cases, is impaired, preventing him following his occupation. There persists a variable amount of fluid in the joint, the ligaments are stretched and slack, and the quadriceps muscle is markedly wasted.

The symptoms closely resemble those of a "loose body," and it is often difficult to differentiate between them. In the case of a body free in the cavity of the joint, the site of the pain varies in different attacks, and the body can sometimes be palpated. Loose bodies wholly or partly composed of bone may be identified with the X-rays.

Attempts may be made to retain the meniscus in position by pads, bandages, or other forms of apparatus, so arranged as to prevent rotation and side-to-side movement at the knee. In the majority of cases, however, the best results are obtained by opening the joint and excising the meniscus in whole or in part, as may be necessary.

The limb is flexed on a splint until the wound has healed, after which massage should be employed and movement of the joint commenced. At the end of two or three weeks the patient is allowed up, wearing an elastic bandage. In most cases the use of the joint is completely regained in from four to six weeks. As an indication of the perfect recovery of the functions of the joint after removal of the meniscus, professional football players are often able to resume their occupation.

#Displacement of the lateral meniscus# is comparatively rare. It is in every way comparable to displacement of the medial meniscus, and is treated on the same lines.

#Torn or Lacerated Meniscus.#--In a large proportion of cases of displaced meniscus in which the condition assumes the recurrent type, it is found, on opening the joint, that, in addition to being unduly mobile, the meniscus is torn or lacerated. The experience of surgeons varies regarding the nature of the laceration. In our experience the most common form is a longitudinal split, whereby a portion of the inner edge of the cartilage is separated from the rest and projects as a tag towards the centre of the joint (Fig. 86). As a rule, it is the anterior end that is torn, less frequently the posterior end. Sometimes the meniscus is split from end to end, the outer crescent remaining in position, while the inner crescent passes in between the condyles and lies curled up against the cruciate ligaments. Occasionally the anterior end is torn from its attachment to the tibia, less frequently the posterior end. In one case we found the meniscus separated at both ends and lying between the bones and the capsule.

The _clinical features_ are similar to those of mobile meniscus with displacement, and as a rule the exact nature of the lesion is only discovered after opening the joint.

The _treatment_ consists in excising the loose tag or the whole meniscus, according to circumstances. The recovery of function is usually complete. It is not advisable to attempt to stitch the torn portion in position.

#Rupture of the Cruciate Ligaments.#--A few cases have been recorded in which, as a result of severe twisting forms of violence, the cruciate ligaments have been torn from their attachments, leaving the joint loose and unstable, so that the tibia and the femur could be moved from side to side on one another. When the disability persists, the joint may be opened and the ligaments sutured in position (Mayo Robson).

#Sprains# of the knee are comparatively common as a result of sudden twisting or wrenching of the joint. In addition to the stretching or tearing of ligaments, there is usually a considerable effusion of fluid into the synovial cavity, and examination with the X-rays occasionally reveals that a portion of bone has been torn away with the ligament--_sprain-fracture_. The swelling fills up the hollows on either side of the patella, and extends for some distance in the synovial pouch underneath the quadriceps. The patella is raised from the front of the femur by the collection of fluid in the joint--"floating patella"--and, if firmly pressed upon, it may be made to rap against the trochlear surface.

A sprain is to be diagnosed from separation of one or other of the adjacent epiphyses, fracture involving the articular ends of the bones, and displacement of the semilunar menisci. On account of the swelling, which obscures the outline of the part, the differential diagnosis is often difficult, but as the swelling goes down under massage it becomes easier. Chief reliance is to be placed upon the bony points retaining their normal relationships, and upon the fact that the points of maximum tenderness are over the attachments of one or other of the collateral ligaments. As the tibial collateral ligament suffers most frequently, the most tender spot is usually over its attachment to the medial aspect of the head of the tibia--less frequently over the medial condyle of the femur.

Unless efficiently treated, a sprain of the knee is liable to result in weakness and instability of the joint from stretching of the ligaments, and this is often associated with effusion of fluid in the synovial cavity (_traumatic hydrops_). This is more likely to occur if the joint is repeatedly subjected to slight degrees of violence, such as are liable to occur in football or other athletic exercises--hence the name "footballer's knee" sometimes applied to the condition.

A further cause of disability, following upon sprains of the knee, is _wasting of the quadriceps muscle_. The stability of the joint, whenever the position of full extension has been departed from, is largely dependent upon its capacity of controlling the amount of flexion, notably in descending a stair or in walking on uneven ground, hence it is that with a wasted quadriceps there is increasing liability to a repetition of the sprain. With each repetition of the sprain, there is an addition to the fluid in the joint, stretching of ligaments, and further wasting of the quadriceps. A form of vicious circle is established in which there is at the same time increased liability to sprain and diminished capacity of recovering from it. Even after the repair of the damaged ligament or the removal of the mobile or torn meniscus, wasting of the quadriceps remains a source of weakness and disability and calls for treatment by massage and electricity.

_Treatment._--In recent and severe cases the patient must be confined to bed, and firm pressure applied over the joint by means of cotton wool and a bandage. This may be removed once or twice a day to admit of the joint being douched, and at the same time it should be massaged and moved to promote absorption of the effusion and prevent the formation of adhesions.

Chronic effusion into the joint is most rapidly got rid of by rest and blistering. If the patient is unable to lie up, massage should be systematically employed, and a firm elastic bandage worn. A patient who has once had a severe sprain of the knee, or who has developed the condition of "footballer's knee," must give up violent forms of exercise which expose him to further injuries, otherwise the condition is liable to be aggravated and to result in permanent impairment of the stability of the joint.

INJURIES OF THE PATELLA

#Fracture of the patella# is a comparatively common injury in adult males. Most frequently it is due to _muscular action_ the patella being snapped across the lower end of the femur by a sudden and forcible contraction of the quadriceps extensor muscle while the limb is partly flexed--as, for example, in the attempt to avoid falling backward. The bone is then broken as one breaks a stick by bending it across the knee, and the line of fracture, which is transverse or slightly oblique, crosses the bone a little below its middle. Fractures produced in this way are almost never compound.

The degree of displacement of the fragments depends upon the extent to which the expansion of the quadriceps tendon is lacerated. As a rule, it is but slightly torn, so that the separation of the fragments does not exceed an inch. In other cases it is widely torn, and the contraction of the quadriceps muscle is then able to separate the fragments by three or four inches, and sometimes causes tilting of the upper fragment. The blood effused into the joint tends still further to increase the separation. As the periosteum is usually torn at a level lower than the fracture, its free margin hangs as a fringe from the proximal fragment, and by getting between the broken ends may form a barrier to osseous union (Macewen).

_Clinical Features._--Immediately the bone breaks, the patient falls, and he is unable to rise again, as the limb is at once rendered useless, and in attempting to do so we have known him to fracture the patella of the other limb. The power of extending the limb is lost, and the patient is unable to lift his foot off the ground. The knee-joint is filled with blood and synovia, which usually extend into the bursa under the quadriceps. The two fragments can be detected, separated by an interval which admits of the finger being placed between them, and which is increased on flexing the knee. On relaxing the quadriceps, the fragments may be approximated more or less completely.

_Prognosis._--In cases with little displacement, if the fragments have been kept in perfect apposition, osseous union may take place, but in the great majority of cases the union is fibrous. The shortening of the quadriceps and the gradual stretching and thinning of the connecting fibrous band may allow of further separation of the fragments (Fig. 88), which to a variable extent interferes with the stability and functions of the limb. The proximal fragment sometimes becomes attached to the front of the femur, and moves with it, and the fibrous band between the two fragments gradually becomes stretched. After bony union has occurred, it is not uncommon for the patella to be fractured again by a fall within a month or two of the original accident.

_Treatment._--It is probably true that the best functional results are most speedily obtained by operative measures. The laceration of the aponeurosis of the quadriceps, the tilting of the fragments, and the interposition of the torn periosteum between them, can in no other way be rectified with certainty. The operation, however, should only be undertaken by those who are familiar with wound technique, and who have the means at their disposal for carrying it out. Operative treatment is specially indicated in young subjects who lead an active life, and in labouring men, particularly those who follow dangerous employments necessitating stability of the knee.

As soon as the wound is healed,--in a week or ten days,--massage and movement of the limb are commenced, and the patient is encouraged to move his limb in bed. At the end of another week he may be allowed up with sticks or crutches.

_Non-operative Treatment._--In the majority of cases occurring in patients who do not follow a laborious occupation or otherwise lead an active life, a satisfactory result can be obtained without having recourse to operation. We have reason to be satisfied with the following method: the patient is kept in bed for a few days, the injured region being supported on a pillow and massaged daily, and the patella moved from side to side as a whole to prevent adhesion to the femur. About the fourth day he is allowed to get about with crutches. As osseous union of the fragments is not essential to a good functional result, and as fibrous union does not necessarily entail any material interference with the usefulness of the limb, no attempt need be made to approximate the fragments, but every effort must be made to maintain the function of the quadriceps muscle and the mobility of the joint.

If it is desired to bring the fragments into contact and to secure osseous union, the limb should be placed upon an inclined plane to relax the quadriceps muscle, and means taken to arrest effusion and to diminish the swelling by systematic massage and a supporting bandage. When, in the course of a few days, this has been accomplished, the attempt is made to approximate the fragments, by fixing a large horseshoe-shaped piece of adhesive plaster to the front of the thigh, embracing the proximal fragment. Extension is made upon this by means of rubber tubing, which is fixed to the foot-piece of the splint. The bandage which binds the limb to the splint should make upward pressure on the distal fragment, or this may be done by a special piece of adhesive plaster with elastic tubing pulling in an upward direction.

The retentive apparatus is kept on for about three weeks, and a rigid, but easily removable, apparatus is thereafter applied, and the patient allowed up on crutches, the limb being massaged and exercised daily to improve the tone of the muscles.

When the fracture is caused by _direct violence_, such as a fall on the knee or the kick of a horse, it may be transverse, oblique, or vertical, but in many cases it is stellate, the bone being broken into several irregular pieces. These comminuted fractures are frequently compound. In transverse and oblique fractures, the displacement depends upon the same causes as in fracture by muscular action. In vertical and stellate fractures, unless the knee has been forcibly flexed after the bone has been broken, there is little or no displacement. The treatment is governed by the same considerations as in fractures by muscular action.

_Old-standing Fracture._--As fibrous union, even with an interval of several inches between the fragments, is not incompatible with a useful limb, it is not often necessary to operate for this condition, but when the usefulness of the limb is seriously impaired, operative treatment is indicated. The operation is carried out on the same lines as for recent fracture, the ends of the bones being rawed and adhesions divided. When the proximal fragment has become attached to the femur, it should be separated and a layer of fascia interposed; it is sometimes necessary to lengthen the quadriceps muscle by making a number of V-shaped incisions through its substance; or a flap may be turned down from the rectus and stitched to the patella and the ligamentum patellae.

When operative treatment is contra-indicated, the patient should be fitted with a firm apparatus which will limit flexion of the knee and support the fragments.

#Dislocation of the patella# is rare. It results from exaggerated muscular movements when the limb is in the fully extended position, or from a blow on one or other edge of the bone. Laxity of the ligaments and knock-knee are predisposing factors. It is sometimes associated with fracture of the edge of the trochlear surface, which renders retention in position difficult.

The _lateral_ is the most common variety--the _medial_ being rare. Either may be complete or incomplete. Sometimes the bone is rotated so that its edge rests on the front of the femur--_vertical_ dislocation; and in a few cases it has been completely turned round, so that the articular surface is directed forwards.

_Clinical Features._--The joint is fixed, usually in a position of slight flexion, and the displaced patella can readily be palpated. The deformity is a striking one, and at first sight suggests a much more serious injury. Although easily reduced, the dislocation is liable to recur.

To effect reduction, the quadriceps must be thoroughly relaxed by extending the leg upon the thigh and flexing the thigh upon the pelvis; the patella is then tilted by making firm pressure on that edge which lies farthest from the middle of the joint, and at the same time pushing towards the middle line. The limb is placed on a posterior splint, and firm elastic pressure made on the joint to prevent or diminish effusion. Massage and movement are carried out from the first.

As the displacement is liable to recur, the patient should wear a firm elastic bandage or a strong knee-cap.

_Permanent and recurrent dislocation of the patella_ will be described later.

FRACTURE OF THE BONES OF THE LEG

The bones of the leg may be broken together or separately.

#Fracture of both Bones.#--The features of this injury depend to a large extent upon the nature of the violence producing it. In fracture by _direct_ violence, such as the passage of a wheel over the limb or a severe blow, the bones give way at the point of impact, and the line of fracture tends to be transverse, both bones being broken at the same level (Fig. 89). There is little or no displacement, and such as there is is angular, and is determined by the direction of the fracturing force.

When the violence is _indirect_, as from a fall on the feet, or a twist of the leg, the tibia usually gives way at the junction of its lower and middle thirds, and the fibula at a higher level (Fig. 90). Torsion of the tibia is probably the most important factor in the production of the fracture, the distal fragment being fixed by the pressure of the foot upon the ground, while the proximal fragment is rotated by the impetus of the body. Both fractures are usually oblique--that in the tibia running from above downward, forward, and medially, and it is generally found that the obliquity of the fibular fracture corresponds with that in the tibia.

There is usually considerable displacement, the weight of the lower portion of the limb causing it to fall backwards and to roll away from the middle line, and the traction of the calf muscles pulling up the heel and pointing the toes. The proximal fragment forms a projection on the front of the limb.

On account of the superficial position of the tibia and the pointed character of the fragments, this fracture is frequently rendered compound by the bone being forced through the skin. The projecting piece of bone is usually the distal end of the proximal fragment. This fracture is often comminuted. It has been observed that when the line of fracture forms the letter V on the subcutaneous surface of the tibia, there is invariably a fissure passing down along the back of the bone into the ankle-joint--a complication which adds to the risk of subsequent stiffness and impaired usefulness of the limb. Apart from this, the ankle is usually sprained in fractures by indirect violence, and we have frequently found the superior tibio-fibular articulation torn open in severe fractures of both bones of the leg from indirect violence.

_Clinical Features._--The tibial fracture is readily recognised by detecting an irregularity on running the fingers along the crest of the shin, and at this point abnormal mobility, tenderness, and crepitus can usually be elicited. It is often difficult to detect the fibular fracture, and it is not always advisable to attempt to do so, especially if the manipulations cause pain or tend to increase the displacement. The condition of the fibula is usually to be inferred by noting the amount of displacement and the extent of mobility of the tibial fragments. Not infrequently the seat of fracture may be recognised by locating a point at which pain is elicited on making pressure over the bone at a distance--pain on distal pressure.

On account of the close connection of the skin to the periosteum on the subcutaneous aspect of the tibia, the tension caused by extravasated blood is often extreme; blisters frequently form over the area of ecchymosis, and when these become infected, sloughing of the skin may take place and the fracture thus be rendered compound.

The vessels and nerves of the leg are seldom seriously damaged.

_Treatment._--If there is marked displacement, reduction is most satisfactorily accomplished under anaesthesia. Traction is made upon the foot and the fragments are manipulated into position, the pointing of the toes and the outward rotation of the foot being at the same time corrected. The normal outline of the foot in relation to the leg is restored when the ball of the great toe, the medial malleolus, and the medial edge of the patella are in the same vertical plane. As in other fractures of the lower extremity, the limb should be placed in the natural position of slight eversion: not with the toes pointing straight forward.

The retentive apparatus to be applied depends upon the tendency to re-displacement, the degree of swelling, and the extent of the damage to the skin.

In the average case, the leg is supported between sand-bags, and massage and movements are employed from the outset. When there is a tendency to re-displacement, the limb may be immediately enclosed in a rigid apparatus, such as lateral poroplastic splints retained in position by an elastic bandage, or a Cline's splint, which can readily be removed to admit of massage. When the fracture is in the lower third of the leg, the ambulatory splint gives excellent results, and is of special service in hospital practice (Fig. 95).

As an emergency appliance, for example for purposes of transport, the _box splint_ (Fig. 91) is simple and efficient. We have not found it effectual in controlling the fragments, particularly in oblique fractures, and it requires constant supervision and readjustment. It consists of two pieces of wood extending from above the knee to an inch or two beyond the sole, and a little broader than the maximum diameter of the leg. These are rolled into the opposite ends of a folded sheet, so as to form two sides of a box, of which the sheet constitutes a third side. It is found advantageous to insert another board, fitted with a foot-piece, between the folds of the sheet forming the third side of the box, to add to the rigidity of the splint, and to aid in controlling the foot. By folding one side of the sheet somewhat obliquely, the box is made a little wider at the knee than at the ankle, and so fits the limb more accurately.

The limb is placed in this box, the sides of which have been carefully padded. Ring pads are applied to take pressure off the condyles, the head of the fibula, the malleoli, and the prominence of the heel, and a large supporting pad is placed behind the tendo calcaneus. A folded towel is laid over the front of the leg, forming a lid to the box, and the whole is bound to the limb by three slip-knots. Finally, the foot is fixed at right angles to the leg and slightly abducted by a figure-of-eight bandage or a piece of elastic webbing. Sand-bags placed alongside serve to steady the limb. In fractures of the lower third of the leg, the box splint may stop short of the knee and the limb may then be suspended in a Salter's cradle, which allows the patient to move about more freely in bed.

To prevent shortening in oblique fractures and in those near the ankle-joint, where it is often difficult to control the lower fragment, extension, applied by weight and pulley, or through a Thomas' knee splint, may be of service. The strapping may be applied only to the distal fragment, but we prefer to carry it to the upper third of the leg. If the overriding of the fragments persists, extension may be taken directly from the bone, the ice-tong callipers gripping the malleoli or the calcaneus.

When the skin is damaged, as it so frequently is on the medial aspect of the tibia, means must be taken to prevent infection.

Massage is carried out daily, and, to prevent stiffness, the ankle is moved from the first. In the course of three weeks, lateral poroplastic splints retained by an elastic bandage may be substituted, and the patient allowed up on crutches. In simple fractures without displacement, union is usually complete in from six to eight weeks, but when the fracture is oblique, comminuted, or compound, union is often delayed, and the functions of the limb may not be fully regained for three or even four months after the accident.

_Operative Treatment._--When overriding cannot otherwise be corrected, it is advisable to replace the fragments by operation. A curved incision with its convexity backward is made over the medial side of the tibia, exposing the fragments, which are then levered into position and if necessary plated or otherwise fixed according to circumstances. It is seldom necessary to deal separately with the fibula. A box splint is applied till the wound has healed, after which a poroplastic splint is substituted and massage commenced.

We do not share in the dissatisfaction expressed by some surgeons, notably Arbuthnot Lane, as to the results obtained by non-operative means in the common fractures of the leg, and do not recommend a systematic resort to operative treatment.

_Un-united fracture_ of the bones of the leg is sometimes met with. It is treated on the same lines as in other situations, but may prove extremely intractable, especially in children, in whom, indeed, it is sometimes incurable.

_Mal-union_, on account of the disability it entails, may call for operative treatment in the form of osteotomy of one or both bones.

_Compound fractures_ of the leg are common, and are treated on the lines already laid down for the treatment of compound fractures in general (p. 25).

#Fracture of the tibia alone#, when due to direct violence, is usually transverse, there is little displacement, and as the fibula retains the fragments in position, union usually takes place rapidly and without deformity. Oblique and spiral fractures result from indirect violence.

#Fracture of the fibula alone# may result from direct violence, and, on account of the support given by the tibia, is usually unattended by displacement. Bennett of Dublin has pointed out that it is common to meet with an oblique fracture of the upper third of the fibula as the result of an outward twist of the ankle while the foot is extended. It is characterised by pain localised at the seat of the break, on moving the foot in such a way as to bring the talus to bear against the fibula. Local pressure also may make the fibula yield and may elicit crepitus. In some cases this fracture is associated with sprain of the ankle-joint. It is often overlooked, and from want of proper treatment may result in prolonged impairment of usefulness.

Fractures of the tibia or fibula alone are treated on the same lines as fractures of both bones, and splints are rarely necessary. The ambulant method is useful in these cases (Fig. 95).