Part 49

Causes.—This condition, as we have seen, may be the result of chronic disease producing structural changes in the tendons, and it may also occur as the result of other affections or some peculiarity independent of this and situated below the fetlock, such as ringbones, sidebones, or traumatic disease of the foot proper. Animals are sometimes predisposed to knuckling, such, for example, as are naturally straight in their pasterns, or animals which are compelled to labor when too young. The hind legs are more predisposed than the fore to this deformity, in consequence of the greater amount of labor they are required to perform as the propelling levers of the body.

Symptoms.—The symptoms of knuckling are easily recognized. The changes in the direction of the bones vary more or less with the degree of the lesion, sometimes assuming such a direction that it almost becomes a true dislocation of the pastern.

The effect of knuckling upon the gait also varies according to the degree of the deformity. As the different degrees of the shortening of the leg affect the motion of the fetlock, the lameness may be very slight or quite extreme. Another consequence of this shortening is such a change in the position of the foot that the heels cease to come in contact with the ground and assume a greater elevation, and the final result of this is soon witnessed in the development of a clubfoot.

Treatment.—To whatever cause the knuckling may be ascribed, it is always a severe infirmity, and there is but little room for hoping to overcome it unless it be during the very first stages of the trouble, and the hope dwindles to still smaller dimensions when it is secondary to other diseases below the fetlock. If it is caused by overworking the animal, the first indication, of course, will be rest. Line firing has proved very efficacious in these cases. The animal must be turned loose and left unemployed. Careful attention should be given to the condition of his feet and to the manner of shoeing, while time is allowed for the tendons to become restored to their normal state and the irritation caused by excessive stretching has subsided. A shoe with a thick heel will contribute to this. If no improvement can be obtained, however, and the tendons though retracted have yet been relieved of much of their thickening, the case is not a desperate one, and may yet be benefited by the operation of tenotomy, single or double—an operative expedient which must be committed to the experienced surgeon for its performance.

SPRUNG KNEES.

Though not positively the result of diseases of the tendons acting upon the knees, we venture to consider this deformity in connection with that which we have just described. It consists in such an alteration in the direction and articulation of the bones which form the various carpal joints that instead of forming a vertical line from the lower end of the forearm to the cannon bone they are so united that the knee is more or less bent forward, presenting a condition caused by the retraction of two of the principal muscles by which the cannon bone is flexed.

Cause.—This flexion of the knee may be a congenital deformity and have continued from the foaling of the animal; or, like clubfoot, it may be the result of heavy labor which the animal has been compelled to perform when too young. It may also be due to other diseases existing in parts below the knee joint.

Symptoms.—This change of direction largely influences the movement of the animal by detracting from its firmness and practically weakening the entire frame, even to the extent of rendering him insecure on his feet and liable to fall. This condition of weakness is sometimes so pronounced that he is exposed to fall even when standing at rest and unmolested, the knees being unable even to bear their portion of the mere weight of the frame. This results in another trouble—that of being unable to keep permanently upright. He is liable to fall on his knees, and by this act becomes presently a sufferer from the lesion known by the term of "broken knees."

Treatment.—Whatever may be the originating cause of this imperfection, it detracts very largely from the usefulness and value of a horse, disqualifying him for ordinary labor and wholly unfitting him for service under the saddle without jeopardizing the safety of his rider. If, however, the trouble is known from the start, and is not the result of congenital deformity or weakness of the knee joint, or secondary to other diseases, rest, with fortifying frictions, may sometimes aid in strengthening the joints; and the application of blisters on the posterior part of the knee, from a short distance above to a point a little below the joint, may be followed by some satisfactory results; but with this trouble, as with knuckling fetlocks, the danger of relapse must be kept in mind as a contingency always liable to occur.

CURB.

This lesion is the bulging backward of the posterior part of the hock, where in the normal state there should be a straight line, extending from the upper end of the point of the hock down to the fetlock.

Cause.—The cause may be a sprain of the tendon which passes on the posterior part of the hock, or of one of its sheaths, or of the strong ligament situated on the posterior border of the os calcis.

Hocks of a certain conformation seems to possess a greater liability to curb than others. They are overbent, coarse, and thick in appearance, or may be too narrow from front to back across the lower portion. This condition may therefore result as a sequence to congenital malformation, as in the case of horses that are "saber-legged." It often occurs, also, as the result of violent efforts, of heavy pulling, of high jumping, or of slipping; in a word, it may result from any of the causes heretofore considered as instrumental in producing lacerations of muscular, tendinous, or ligamentous structure.

Symptoms.—A hock affected with curb will present at the outset a swelling more or less diffuse on its posterior portion, with varying degrees of heat and soreness, and these will be accompanied with lameness of a permanent character. At a later period, however, the swelling will become better defined, the deformity more characteristic, the prominent, curved line readily detected, and the thickness of the infiltrated tissue easily determined by the fingers. At this time, also, there may be a condition of lameness, varying in degree, while at others, again, the irregularity of action at the hock will be so slight as to escape detection, the animal betraying no appearance of its existence.

A curb constitutes, by a strict construction of the term, an "unsoundness," since the hock thus affected is less able to endure severe labor, and is more liable to give way with the slightest effort. Yet the prognosis of a curb can not be considered to be serious, as it generally yields to treatment, or at least the lameness it may occasion is generally easily relieved, though the loss of contour caused by the bulging will always constitute a blemish.

Treatment.—On the first appearance of a curb, when it exhibits the signs of an acute inflammation, the first indication is to subdue it by the use of cold applications, as intermittent or constant irrigation or an ice poultice; when these have exhausted their effect and the swelling has assumed better defined boundaries, and the infiltration of the tendons or of the ligaments is all that remains of a morbid state, then every effort must be directed to the object of effecting its absorption and reducing its dimensions by pressure and other methods. The medicaments most to be trusted are blisters of cantharides and frictions with ointments of iodin, or, preferably, biniodid of mercury. Mercurial agents alone, by their therapeutic properties or by means of the artificial bandages which they furnish by their incrustations when their vesicatory effects are exhausted, will give good results in some instances by a single application, and often by repeated applications. The use of the firing iron must, however, be frequently resorted to, either to remove the lameness or to stimulate the absorption. We believe that its early application ought to be resorted to in preference to waiting until the exudation is firmly organized. Firing in dull points or in lines will prove as beneficial in curb as in any other disease of a similar nature.

LACERATED TENDONS.

This form of injury, whether of a simple or of a compound character, may become a lesion of a very serious nature, and will usually require long and careful treatment, which may yet prove unavailing in consequence either of the intrinsically fatal character of the wound itself or the complications which have rendered it incurable.

Cause.—Like all similar injuries, they are the result of traumatic violence, such as contact with objects either blunt or sharp; a curb-stone in the city; in the country, a tree stump or a fence, especially one of wire. It may easily occur to a runaway horse when he is "whipped" with fragments of harness or "flogged" by fragments of splintered shafts "thrashing" his legs, or by the contact of his legs with the wagon he has overturned and shattered with his heels while disengaging himself from the wreck.

Symptoms.—It is not always necessary that the skin be involved in this form of injury. On the contrary, the tegument is frequently left entirely intact, especially when the injury follows infectious diseases or occurs during light exercise after long periods of rest in the stable. Again, the skin may be cut through and the tendons nearly severed. A point a little above the fetlock is usually the seat of the injury. But irrespective of this, and whether the skin is or is not implicated, the symptoms resemble very much those of a fracture. There is excessive mobility, at least more than in a normal state, with more or less inability to carry weight. There may be swelling of the parts, and on passing the hands carefully along the tendon to the point of division the stumps of the divided structure will be felt more or less separated, perhaps wholly divided. The position of the animal while at rest and standing is peculiar and characteristic. While the heels are well placed on the ground, the toe is correspondingly elevated, with a tendency to turn up—a form of breaking down which was described when speaking of the fracture of the sesamoids. Carrying weight is done only with considerable difficulty, but with comparatively little pain, and the animal will unconsciously continue to move the leg as if in great suffering, notwithstanding the fact that his general condition may be very good and his appetite unimpaired.

The effect upon the general organism of compound lacerated wounds of tendinous structures, or those which are associated with injuries of the skin, are different. The wound becomes in a short time the seat of a high degree of inflammation, with abundant suppuration filling it from the bottom; the tendon, whether as the result of the bruise or of the laceration, or of maceration in the accumulated pus, undergoes a process of softening, and necrosis and sloughing ensue. This complicates the case and probably some form of tendinous synovitis follows, running into suppurative arthritis, to end, if close to a joint, with a fatal result.

Prognosis.—The prognosis of lacerated tendons should be very conservative. Under the most favorable circumstances a period of from six weeks to two months will be necessary for the treatment, before the formation of the cicatricial callus and the establishment of a firm union between the tendinous stumps.

Treatment.—As with fractures, and even in a greater degree, the necessity is imperative, in the treatment of lacerated tendons, to obtain as perfect a state of immobility as can be obtained compatibly with the disposition of the patient; the natural opposition of the animal, sometimes ill-tempered and fractious at best, under the necessary restraint causing at times much embarrassment to the practitioner in applying the necessary treatment. Without the necessary immobility there can be no close connection of the ends of the tendons. To fulfill this necessary condition the posterior part of the foot and the fetlock must be supported and the traction performed by them relieved, an object which can be obtained by the use of the high-heeled and bar shoe, or possibly better accomplished with a shoe of the same kind extending about 2 or 2-1/2 inches back of the heels. The perfect immobility of the legs is obtained in the same way as in the treatment of fracture, with splints, bandages, iron apparatus, plaster of adhesive mixtures, and similar means. So long as the dressings remain in place undisturbed and no chafing or other evidence of pain is present, the dressings may be continued without changing, the patient being kept in the slings for a period sufficient to insure the perfect union of the tendons. For a compound lesion when there is laceration of the skin some special care is necessary. The wound must be carefully watched and the dressings removed at intervals of a few days or as often as may be needful, all of which additional manipulation and extra nursing, however indispensable, still adds to the gravity of the case and renders the prognosis more and more serious. When the tendons have sloughed in threads of various dimensions, or if in the absence of this process of mortification healthy granulations should form and fill up the wound, still very careful attention will be required, the granulating ends of the tendons having a tendency to bulge between the edges of the skin and to assume large dimensions, forming bulky excrescences or growths of a warty or cauliflower appearance, the removal of which becomes a troublesome matter.

The union of the tendons will at times leave a thickening of varying degree near the point of cicatrization, the absorption of which becomes an object of difficult and doubtful accomplishment, but which may be promoted by moderate blistering and the use of alterative and absorbent mixtures or perhaps the fire iron. A shoe with heels somewhat higher than usual will prove a comfort to the animal and aid in moderating and relieving the tension of the tendons.

RUPTURE OF THE FLEXOR METATARSI.

This is a muscle of the anterior part of the shank. It is situated in front of the tibia, and is of peculiar formation, being composed of a muscular portion with a very powerful tendon, which are at first distinct and separate, to be intimately united lower down, and terminating at the lower end by a division into four tendinous bands. It is a powerful muscle of the hinder shank bone, and also acts as a strong means of support for the stifle joint; that is, of the articulation of the thigh and shank bone, in front and outside of which it passes. Its situation and its use cause it to be liable to severe stretching and straining, and a rupture of some of its fibers is sometimes the consequence.

Cause.—This injury may be the result of a violent effort of the animal in leaping over a high obstacle; in missing his foothold and suddenly slipping backward while powerfully grasping the ground with the feet in striving to start a heavily loaded vehicle; in making a violent effort to prevent a probable fall; or in attempting to lift the feet from miry ground.

Symptoms.—The accident is immediately followed by disability which will vary according to the true seat of the injury and the period of its duration. This rupture will not prevent the horse from standing perfectly and firmly on his feet when kept at rest, and while no muscular efforts are required from him there is no appearance of any lesion or unsoundness. An attempt to move him backward, however, will cause him to throw all his weight upon his hind-quarters, and he will refuse to raise his foot from the ground. If compelled to do so, or required to move forward, the hock being no longer capable of flexion, the muscle which effects that movement being the injured one, the opposite muscles, the extensors, acting freely, the entire lower part of the leg, from the hock down, will be suddenly, with a jerk, extended on the tibia or shank bone, and simultaneously with this the tendo Achillis, the cord of the hock, the tendons of the extensors of the hock will be put in a wrinkled and relaxed condition. The leg is behind the animal and the toe rests on the ground. Examination of the fore part of the shank from the stifle down to the hock may reveal soreness, and possibly some swelling and heat at the seat of the lesion.

Treatment.—Our experience with injuries of this form convinces us that, generally speaking, they are amenable to treatment. Provided a sufficient time has been allowed for union to take place, very few instances in which radical recovery has not been effected have come to our knowledge. The more flexed the leg can be kept, the quicker will it heal.

In these cases, as in those of simple laceration of tendons, already considered, the indications resemble those which apply in the treatment of fractures, as near as coaptation of the lacerated ends is possible, with immobility, being the necessary conditions to secure. The first is a matter of very difficult accomplishment, by bandaging alone, and some have recommended instead the application of charges or blisters in order to compel the animal to keep more quiet.

To secure the necessary immobility the animal should be placed in slings snugly applied, and kept in a narrow stall. He should also be tied short, and restrained from any backward movement by ropes or boards, and should, moreover, be kept in as quiet a temper as possible by the exclusion of all causes of irritation or excitement. Weeks must then elapse, not less, but frequently more than six, often eight, before he can be considered out of danger and able to return to his labor, which should for a time be light and easy, and gradually, if ever, increased to the measure of a thoroughly sound and strong animal. If he is used too soon the newly formed tissue between the ends of the muscle will be liable to stretch and leave the flexor muscle too long and permanently displaced.

SUNDRY ADDITIONAL AFFECTIONS OF THE EXTREMITIES.

Among these there are three which will principally occupy our attention, and, which may be considered as forming a single group. In some parts of the legs may be found certain peculiar little structures of a saclike formation, containing an oily substance designed for the lubrication of the parts upon which they are placed for the purpose of facilitating the movements of the tendons which pass over them. These little sacs or muco-synovial capsules, under peculiar conditions of traumatism, are liable to become subject to a diseased process, which consists principally in a hypersecretion of their contents and an increase in dimensions, and they may undergo peculiar pathological changes of such character as to disable an animal, and in many instances to cause serious blemishes which can but depreciate its value. These growths, which are known as hygromata, may result from external violence, as blows or bruises, and may appear in the form of small, soft tumors, painless and not inflammatory in character, but, by a repetition of the cause or renewal of violence, liable to acquire increased severity. Severe inflammation, with suppuration, may follow, which, filling up the cavity, the walls will become thickened and hard, resulting in the formation of a tumor.

The elbow, the knee, and the hock are the parts of the body where these lesions are ordinarily found, and on account of their peculiar shape and the position they occupy they have received the denomination "capped." They will be considered in their peculiar aspect.

CAPPED ELBOW.

Capped elbow, or "shoe boil," is a term applied to an enlargement often found at the point of the elbow.

Cause.—This lesion is due to injury or pressure of the part while it is resting on the ground. The horse, unlike the cow, does not rest directly on the under surface of the sternum, or breastbone, on account of its sharp, ridge-like formation. He rests more on the side of the breastbone and chest, and consequently the leg which is flexed under the body is subject to considerable pressure. If the leg is flexed under the body so that the hoof or shoe is directly in contact with the elbow, which may occur in horses having an extremely long cannon bone or excessive length in the shoes, the greater part of the weight of the chest is concentrated at this point and the pressure may cause a bruise or an inflammation.