LAMENESS OF THE HORSE VETERINARY PRACTITIONERS' SERIES, NO. 1 TEXT

Treatment.--The most practical method of handling bog spavin consists in aspiration of synovia and injection of tincture of iodin. Discretion should be employed in selecting subjects for treatment, regardless of the manner in which such cases are to be handled. Where there exists chronic distension of the joint capsule of several years' standing in old or weak subjects, needless to say, recovery is not likely to result. When animals are vigorous and two or three months' time is available, treatment may be begun with reasonable hope for success. The average subject is handled standing and can be restrained with a twitch, sideline and hood. Aspirating needles and all necessary equipment must be in readiness (sterile and wrapped in aseptic cotton or gauze) so that no delay will occur from this cause when the operation has been started. The central or most prominent part of the distended portion of the capsule is chosen for perforation and an area of an inch and a half in diameter is shaved. The skin is cleansed and then painted with tincture of iodin. The sterile aspirating needle is pushed through the tissues and into the capsule with a sudden thrust. With a large and sharp needle (fourteen gauge), synovia can be drawn from the cavity in most instances and the subject usually offers no resistance. By compressing the distended capsule and surrounding structures with the fingers, considerable synovia may be evacuated. In singular instances, no synovia is to be aspirated with the needle, and in such cases the amount of iodin injected needs be increased, possibly twenty-five per cent., as experience will indicate. From two to five cubic centimeters of U.S.P. tincture of iodin is injected through the aspirating needle into the synovial cavity of the joint, and the exterior of the parts are vigorously massaged immediately after injection to stimulate distribution of the iodin throughout the synovial cavity. Where a bilateral affection exists, two or three weeks' time should intervene between the treatments of each leg. A sterile metal syringe equipped with a slip joint for the needle is well adapted to this operation. Lubrication of the plunger with heavy sterile vaseline or glycerin will prevent the syringe from being ruined by the iodin. Following the injection, the subject is kept in a stall or in a suitable paddock, so that conditions may be observed for four or five days. The object sought by the introduction of iodin is not only for a local effect upon the synovial membranes in checking secretions, but the production of an active inflammation and great swelling, which will remain from four weeks to three months subsequent to the injection. This periarticular swelling should produce and maintain a constant pressure over the entire affected parts for a sufficient length of time until normal tone is re-established. In some cases, swelling does not develop as the result of a single injection of iodin. When marked swelling has not taken place within five days, none will occur and a repetition of the injection may be made within ten days after the first treatment has been given. One may safely increase the amount of iodin at the second injection in such cases by one-fourth to one-third. In Europe this method of treating bog spavin has been employed by Leblanc, Abadie, Dupont and others according to Cadiot; but Bouley, Rey, Lafosse and Varrier used it with bad results. Where a perfect technic is executed (and no other is excusable in this operation), no infection will occur if a reasonable amount of iodin is injected. The dilution of iodin with an equal amount of alcohol has been practised by the author in many cases, but later this was found unnecessary. Other methods of treatment have been used with success. Perhaps the most heroic consists in opening the joint capsule with a bistoury or with the actual cautery. Such practice is too hazardous for general use and is not to be recommended, although good results should follow the employment of such methods if infectious arthritis does not occur. Line firing over the distended capsule is a practical method of treatment. This is attended with good results in young animals in many cases, but considerable blemish is caused when sufficient irritation is produced to stimulate resolution. Vesication also is successfully employed in some instances. However, only cases of recent origin in young animals--colts of two years or younger--yield to blistering, and in some affected colts no doubt recovery would have been spontaneous had no treatment been instituted. Ligation of the saphenous vein at two points, one above and the other below the distended ligamentous capsule, is an old operation, which has undoubtedly given good results in some cases, although it does not seem to be a rational procedure. After-Care.--After swelling has fully developed--which occurs within a week--the subject is turned to pasture and no attention is necessary thereafter. A gradual subsidence of the swelling occurs and in the average instance, this completely resolves within six or eight weeks. Complete recovery succeeds the aspiration-and-injection-treatment in about seventy-five per cent of cases as the result of one operation, and subjects may be gradually and carefully returned to work in about sixty days after treatment has been given. Distension of the Tarsal Sheath of the Deep Digital Flexor. (Thoroughpin.) The terms "thoroughpin" or "throughpin" are translations from the French _vessignon chevillé_ and have the same significance. They are so named because of the diametrically opposed distensions of the sheath of the deep flexor tendon in such manner that the distensions appear to be due to a supporting peg. Anatomy.--The theca through which the deep digital flexor (perforans) plays in the tarsal region, begins about three inches above the inner tibial malleolus and extends about one-fourth of the way down the metatarsus. The posterior part of the capsular ligament of the hock joint is very thick in its most dependent portions and is in part cartilaginous, forming a suitable groove for the passage of the deep flexor tendon. [Illustration: Fig. 57--Thoroughpin. Showing distension of the sheath of the deep flexor tendon as it protrudes antero-externally to the fibular tarsal bone (calcaneum).] Etiology and Occurrence.--Strains and sequellae to debilitating diseases constitute the usual causes of this affection. As a result of acute synovitis a chronic synovial distension of the tarsal sheath occurs. Bog spavin is often present in case of thoroughpin but the two conditions are separate and distinct excepting in that both may occur simultaneously and as the result of the same cause. Some animals are undoubtedly predisposed to disease of synovial structures. The average horse that has been subjected to hard service on pavements or hard roads at fast work suffers synovial distension of bursae, thecae or of joint capsules. Some of the well bred types such as the thoroughbred horses may be subjected to years of hard service and still remain "clean limbed" and free from all blemishes. Thus it seems that subjects of rather faulty conformation, animals having lymphatic temperaments and the coarse-bred types, are prone to synovial disturbances such as thoroughpin, bog spavin, etc., sometimes having both legs affected. [Illustration: Fig. 58--Fibrosity of tarsus as a complication in chronic thoroughpin.] Symptomatology.--Thoroughpin is characterized by a distended condition of the tarsal sheath which is manifested by protrusions anterior to the tendo Achillis. However, where but moderate distension of the sheath exists, there is little, if any, bulging on the mesial side of the hock and but a small hemispherical enlargement is presented on the outer side of the tarsus, anterior to the summit of the os calcis. In some instances the protruding parts assume large proportions, but always, because of the relationship between the fibular tarsal bone (calcaneum) and the tendon sheath, the larger protrusion is situated mesially. 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_. [Illustration: Fig. 59--Another view of same case as illustrated 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 practitioner 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 quantity 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 quantity of potassium 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 mass 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 mass 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. [Illustration: 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 constitutes 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, substituting 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 fashioned 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 principal causes of interfering. Horses that are "base