Lameness of the Horse Part 25

During the acute inflammatory stage there is marked lameness present but this soon subsides when local antiphlogistic agents are applied to the parts. In fact, spontaneous relief from lameness usually results in the course of ten days' time following the appearance of thoroughpin. No lameness marks the advent of this affection when it develops as the result of continuous strain and concussion occasioned by hard service, and local changes tend to remain in _status quo_.

[Ill.u.s.tration: Fig. 59--Another view of same case as ill.u.s.trated in Fig.

58.]

Treatment.--Rest and the local application of heat or cold will suffice to promote resolution of acute inflammation and lameness when present will subside within two weeks. In chronic affections, however, the matter and manner of effecting a correction of the condition--distended tarsal sheath--merit careful consideration. While drainage of distended thecae and bursae by means of openings made with hot irons was practiced by the Arabs, centuries ago, and good results have attended such heroic corrective measures, nevertheless the occasional serious complications which result from infection likely to be introduced in following such procedures, cause the prudent and skilful pract.i.tioner to employ safer methods of treatment.

The application of blistering agents is of no value in stimulating resorption of an excessive amount of synovia in chronic cases and the actual cautery when employed without perforation of the synovial structure, is of little benefit. Trusses or mechanical appliances for the purpose of maintaining pressure upon the distended parts are of no practical value because of the great difficulty of keeping such contrivances in position. They usually cause so much discomfort to the subject that they are not tolerated.

A very practical and fairly successful method of treatment consists in the aspiration of a quant.i.ty of synovia and injecting tincture of iodin.

Cadiot recommends the drainage of synovia with a suitable trocar and cannula and injecting a mixture consisting of tincture of iodin, one part, to two parts of sterile water, to which is added a small quant.i.ty of pota.s.sium iodid. The latter agent is added to prevent precipitation of the iodin. This authority (Cadiot) further advocates the removal of practically all of the synovia that will run out through the cannula and the immediate introduction of as much as one hundred cubic centimeters of the above mentioned iodin solution. This solution is allowed to remain in the synovial cavity a few minutes and by compressing the tissues surrounding the tendon sheath, the evacuation of as much of the contents of the synovial cavity as is practicable, is effected.

Subsequently the subject is allowed absolute rest and more or less inflammatory reaction follows. In some cases there occur marked lameness and some febrile disturbance, but where a good technic is carried out, no bad results follow. At the end of four weeks' time, horses so treated may be returned to service, but the full beneficial effect of such treatment is not experienced until several months' time have elapsed.

Where good facilities for executing a careful technic in every detail are at hand, incision of the tarsal sheath, evacuation of its contents and uniting its walls again by means of sutures and providing for drainage with a suitable drainage tube, may be practiced. This manner of treatment has been satisfactory in the hands of a number of surgeons.

Capped Hock.

Enlargements which occur upon the summit of the os calcis, whether hypertrophy of the skin and subcuticular fascia, the result of injury or repeated vesication, distension of the subcutaneous bursa or injury to the superficial flexor tendon (perforatus) or its sheath, are generally known as capped hock. However, the term should be restricted to use in reference to distensions of synovial structures of that region.

Etiology and Occurrence.--Usually there occurs a hygromatous involvement of the subcutaneous bursa due to contusion. As in bog spavin, following certain infectious diseases (influenza, purpura hemorrhagica, etc.) there remains a distended condition of the subcutaneous bursa, after swelling of the member has subsided. In feeding pens where numbers of young mules are kept in crowded quarters many cases may be observed. In some instances where violent contusions result from kicking cross-bars of wagon shafts (by nymphomaniacs or in habitual kickers where there is opportunity for doing such injury) the superficial flexor tendon and its synovial apparatus are injured and a more serious condition may result.

Symptomatology.--In acute and extensive inflammation of the parts, lameness is present, but in the average case no inconvenience to the subject results. The prominent site of the affection is cause for an unsightly blemish. This is undesirable, particularly in light-harness or saddle horses. These affections are characterized by a fluctuating ma.s.s which has a thin wall and in all cases of long standing the condition is painless.

By careful palpation one may readily distinguish between a hygromatous condition of the superficial bursa and involvement of the underlying structures. Affection of the expanded portion of the flexor tendon and contiguous structures makes for an organized ma.s.s of tissue which is somewhat dense and in some instances painful to the subject when manipulated. This is particularly noticeable in cases where the parts are regularly and repeatedly injured as in habitual kickers.

[Ill.u.s.tration: Fig. 60--"Capped hock." Distension of the bursa over the summit of the os calcis.]

Treatment.--In acute inflammation, antiphlogistic applications are indicated and the subject must be kept quiet. The matter of bandaging the hock is a difficult problem in some cases and needs be done with care. As has been previously stated in this volume, the tarsus needs to be well padded with cotton before the bandages are applied and only a moderate degree of tension is employed in applying the bandages lest anemic-necrosis result from pressure. In distension of the superficial bursa, after clipping the hair over a liberal area and preparing the skin by thoroughly cleansing and painting with tincture of iodin, the capsule is incised with a bistoury. An incision about an inch in length, situated low enough to provide drainage, is made through the tissues and the contents are evacuated. Tincture of iodin is injected into the cavity and the parts are covered with cotton and bandaged. No after-care is necessary except to retain the dressing in position, which is not difficult in the average case if the subject is kept tied. If much resistance is exhibited, such as extreme flexion of the bandaged hock, the animal may be put in a sling and little if any objection to the bandage will be offered thereafter. The wound may be dressed at the end of forty-eight hours and no redressing will be necessary in the average instance if infection is not present. But slight local disturbance and little distress to the subject result in cases so treated even when infection occurs, but a good technic is possible of execution in most instances and no infection should take place.

The surgical wound heals in two or three weeks and inflammation gradually subsides. Bandages are retained one or two weeks, as the case may require, and subsequently a good wound lotion may be employed several times daily. A good lotion for such cases as well as in many others has long been employed with success by Dr. A. Trickett of Kansas City. It consists of approximately equal parts of glycerin, alcohol and distilled extract of witch hazel, to which is added liquor cresolis compositus, two percent, and coloring matter q.s.

Complete resolution does not occur in the average case. There remains some hyperplastic tissue and even where the enlargement is slight, the prominent situation of the affection precludes its being unnoticed.

In disease of the flexor tendon and its bursa where contiguous inflammation of tissue is present, the parts are blistered or fired.

Line firing is beneficial in such instances but in all cases the cause is to be removed if possible.

Rupture and Division of the Long Digital Extensor (Extensor Pedis).

Etiology and Occurrence.--Because of the fact that the long digital extensor is the only extensor of the phalanges of the pelvic limb, its rupture or division const.i.tutes a troublesome condition, which in some cases does not readily respond to treatment.

Rupture of this tendon may occur during work on rough and uneven roads, particularly in range horses that are ridden over ground that is burrowed by gophers or prairie dogs; in such cases, horses are apt to suddenly and violently turn the foot in position of volar flexion, thereby causing undue strain to the digital extensor and its rupture sometimes follows. In foals of one or two days of age, this tendon is sometimes found parted or ruptured and the condition may be bilateral.

As the result of accidents, the digital extensor may be divided and when the wound becomes contaminated, as it does because of the marked volar flexion (knuckling) which occurs during the course of this affection, regeneration of tissue is checked and recovery is tardy.

Symptomatology.--There is no interference with ability to sustain weight in such cases, when the foot is placed in normal position; but immediately upon attempting to walk, the toe is dragged, and if weight is borne with the affected member, it comes upon the anterior face of the fetlock. The flexors are not antagonized and if there be an open wound the parts soon become contaminated; or, in rupture, if animals travel about very much, there soon occurs necrosis of the tissues of the anterior fetlock region and the condition is rendered incurable. Cases are reported of animals that have suffered rupture of the long digital extensor and the subjects learned to throw the member forward during extension, subst.i.tuting for the extensor tendon the pendulum-like momentum which the foot affords when so employed; and a walking and even a trotting pace was possible without doing injury to the fetlock region.

Where a subcutaneous division exists as in rupture, the divided ends of the tendon may be definitely recognized by palpation.

Treatment.--Subjects are best put in slings and kept so confined until regeneration of tendinous structures has been completed. This requires from six weeks to two months' time. In addition, the extremity is kept in a state of extension by means of suitable splints and shoes,--a shoe equipped with an extension at the toe and perforated so that a steel brace may be hooked into the perforation and the brace fas.h.i.+oned to be buckled to the upper metatarsal region. When braces are placed in front of the foot, great care is necessary in properly padding the member with cotton lest sloughing from pressure occurs at the coronet; but this does not apply in rupture of extensors so much as where flexors are ruptured.

Open wounds are treated along general surgical lines, dressed as frequently as occasion demands, and recovery will be complete in a few months' time unless much of the tendon has been destroyed. In one instance, the author had occasion to observe such a condition, which, because of the extensive destruction of tendon and lack of facilities for giving proper attention to the subject, results were so unfavorable that it was deemed necessary to destroy the animal.

Wounds From Interfering.

When, during locomotion, injury is inflicted upon the mesial side of an extremity by the swinging foot of the other member, the condition is termed interfering.

Etiology and Occurrence.--Faulty conformation, bad shoeing and over-work are the princ.i.p.al causes of interfering. Horses that are "base narrow" or that have crooked legs are quite apt to interfere. Shoes that are put on a foot that is not level or applied in a twisted position, or shoes wide at the heel will often cause interfering and injury. Animals that are driven at fast work until they become nearly exhausted may be expected to interfere. Such cases are frequently observed in young horses that are driven over rough roads, particularly when so nearly exhausted or weakened from disease or inanition that the feet are dragged forward rather than picked up and advanced in the normal manner.

Symptomatology.--Wounds inflicted by striking the extremities in this manner present various appearances and occasion dissimilar manifestations. The hind legs are almost as frequently affected as the front and the fetlock region is most often injured, though wounds may be inflicted to the coronet. In front, the carpus is sometimes the site of injury.

When only an abrasion is caused, little if any lameness occurs, but where interfering is continued and nerves are involved or subfascial infection and extensive inflammation succeed such abrasions, marked lameness and evidence of great pain are manifested. Frequently, in chronic cases affecting the hind leg, the fetlock a.s.sumes large proportions, and at times during the course of every drive the subject strikes the inflamed part, immediately flexing and abducting the injured member, and the victim hops on the other leg until pain has somewhat subsided.

Interfering is much more serious in animals that are used at fast work than in draft horses. In light-harness or saddle horses, it may render the subject practically valueless or unserviceable if the condition cannot be corrected.

Treatment.--Wherever possible, cause is to be removed and if animals are properly used, ordinary interfering wounds will yield to treatment.

If the shoeing is faulty, this should be corrected, the foot properly prepared and leveled before being shod and suitable shoes applied. In young animals that become "leg-weary" from constant overwork, rest and recuperation are necessary to enhance recovery. In such cases it will be found that very light shoes, frequently reset, will tend to prevent injury to the fetlock region such as characterizes these injuries of hind legs.

Palliative measures of various kinds are employed where cause is not to be removed and a degree of success attends such effort. In draft horses or animals that are used at a slow pace, s.h.i.+elds of various kinds are strapped to the extremity and protection is thus afforded. Or, large encircling pads of leather, variously constructed, serve to cause the subject to walk with the extremities apart.

Interfering shoes of different types are of material benefit in many instances. Often the principle upon which corrective shoeing is based is that the mesial (inner) side of the foot is too low; the foot is consequently leveled and the inner branch of the shoe is made thicker than the outer, altering the position of the foot in this way. This is productive of desirable results. However, much depends upon the manner in which the foot in motion strikes the weight-bearing member as to the corrective measures that are indicated. This belongs to the domain of pathological shoeing and the reader is referred to works on this subject for further study of this phase of lameness.

Lymphangitis.

Excluding glanders, in the majority of instances, lymphangitis in the horse, such as frequently affects the hind legs, is due to the local introduction of infectious material into the tissues as a result of wounds. However, one may observe in some instances an acute lymphangitis which affects the pelvic limbs of horses and no evidence of infection exists. Consequently, lymphangitis may be considered as _infectious_ and _non-infectious_.

INFECTIOUS LYMPHANGITIS.

Etiology and Occurrence.--Traumatisms of the legs frequently result in infection and when such injuries are near lymph glands, even though the degree of infection be slight, more or less disturbance of function of the muscles in the vicinity of such glands occurs and lameness follows.

The prescapular, axillary and cubital lymph glands when in a state of inflammation, cause lameness of the front leg, and the superficial inguinal and deep inguinal lymph glands not infrequently become involved also. Because of the location of these lymph glands, they are subject to comparatively frequent injury and inflammation, causing lameness more often than other lymph-gland-affections.

Small puncture wounds in the region of the elbow are often met with.

These may be inflicted when horses lie down upon sharp stumps of vegetation or shoe-calk injuries may be the means of introducing contagium, and an infectious inflammation results. Abscess formation, the result of strangles or other infection in the prescapular glands, may be observed at times. Following castration, the inguinal lymph glands may become involved in an infectious inflammation and locomotion is impeded to a marked degree. Horses running at pasture sometimes become injured by trampling upon pieces of wood, causing one end of these or of various implements to become embedded in the soft earth and the other end to enter at the inguinal region and even penetrate the tissues to and through the skin and fascia just below the perineal region.

Nail punctures resulting in infection frequently cause an infectious lymphangitis and a marked and painful swelling of the legs supervenes.

[Ill.u.s.tration: Fig. 61--Chronic lymphangitis. Showing hypertrophy of the left hind leg, due to repeated inflammation.]

Symptomatology.--Lameness, mixed or swinging-leg, signalizes the presence of acute lymphangitis. There is always more or less swelling present and manipulation of the affected parts gives pain to the subject. Depending upon the character of the infection and its extent, there is presented a varying degree of const.i.tutional disturbance. There may be a rise in temperature of from two to five degrees, and in such instances there is an accelerated pulse. Where much intoxication is present, anorexia and dipsosis are to be noticed.

Swelling may increase gradually and in time discharge of pus may take place spontaneously without drainage being provided for, if the character of the infection does not cause early death. In these cases lameness is p.r.o.nounced and the cause of the disturbance is to be sought, particularly if the condition be due to a nail puncture.

[Ill.u.s.tration: Fig. 62--Elephantiasis.]