Chapter 12

Being almost inelastic and not well supplied with blood, tendinous tissue is slowly regenerated, and so much time is required for complete recovery to take place in tendinitis, that affected animals seldom fully recover before they are in service or vigorously exercising at will. As a result, complete recovery is delayed or prevented.

The extensor tendons, because of the nature of their function, are very seldom strained; they are often bruised and occasionally divided, but unlike this condition in the flexors, tendinitis of the extensors is of rare occurrence.

For a concise discussion of this subject the most practical classification is one made on a chronological basis and we may then consider tendinitis as _acute_ and _chronic_.

ACUTE TENDINITIS.

Etiology and Occurrence.--Causes of tendinitis, as in almost all diseases, may be considered under the heads of predisposing and exciting. Among the predisposing causes of tendinitis may be mentioned, faulty conformation. Everything which has to do with increasing the strain upon tendons adds to the probability of their being over-taxed. Long, sloping, pastern bones; disproportionate development of parts, such as a heavy body and small, weak tendons and long hoofs, are the principal factors which usually predispose to tendinous sprains. Degenerative changes which take place in tendons following constitutional diseases such as influenza may also be classed as a predisposing cause.

Excessive strain when put upon tendons in any possible manner, such as is occasioned in running and jumping; making missteps and catching up the weight of the body with one foot, when the force thus thrown upon the supporting structure is great because of momentum gained at a rapid pace, are exciting causes of tendinitis.

Symptomatology.--In all cases of acute tendinitis there is presented a characteristic attitude by the subject. Volar flexion in a sufficient degree to relax the inflamed structures is always evident. The foot may be rested on the toe or placed slightly in advance of the one supporting weight, but the fetlock is always thrown forward. More or less swelling of the inflamed tendons is present. Where the deep flexor (perforans) is involved swelling is marked and with swelling there is present the other symptoms of inflammation--heat and supersensitiveness.

In manipulating tendons for the purpose of detecting supersensitiveness, care must be taken so that no false conclusion be drawn, because of the aversion many horses have to submitting to palpation of the tendons even when they are in a normal condition.

Supporting-leg-lameness is present and varies in degree with the intensity of the pain caused by weight bearing. In many instances, as soon as the subject has traveled a considerable distance, lameness diminishes or discontinues. As soon as the affected animal is permitted to stand long enough to "cool out" there is a return of the lameness, which is then marked.

No difficulty is encountered in making a practical diagnosis in tendinitis; that is, one may fail to readily recognize the extent of the involvement as it affects the superficial flexor tendon, for instance, but this has no practical bearing on the prognosis and treatment, when existing inflammation of the deep flexor is recognized.

The course of each tendon is readily outlined by palpation; all parts are easily manipulated; and with experience one may readily recognize the extent and degree of the inflammation.

Treatment.--In some cases of acute tendinitis, pain is intense and the application of cold packs during this stage is very beneficial in that pain is controlled and inflammation subsides. The extremity may be bandaged with a liberal quantity of absorbent cotton or with woolen material. Ice water is then poured around the bandaged member every fifteen minutes and this should be continued for about forty-eight hours. In some cases this treatment is not necessary for more than twelve hours; at the end of this length of time, pain has subsided and the acute stage of inflammation has passed or its intensity has been diminished.

Following the application of cold packs, the use of a poultice such as some of the sterile, medicated muds, is of marked benefit. The author has made use of tincture of iodin and glycerin in the proportion of one part of iodin to seven parts glycerin, with very satisfactory results. This combination is hygroscopic, anodyne and antiseptic and is easily applied. A liberal quantity is directly applied all around the affected tendons and the leg covered with a heavy layer of cotton, and this is snugly held in position with bandages. The application may be used once or twice daily, or if it is thought necessary, an attendant may pour a quantity of the iodized-glycerin around the leg and under the bandage once daily without removing the cotton and bandage. Needless to say, absolute rest is imperative.

When all evidence of acute inflammation has subsided vesication is indicated. At this stage walking exercise is beneficial and the subject may be allowed the freedom of a paddock.

Some practitioners are partial to the use of the actual cautery in these cases, but it is doubtful if it is necessary to produce such a great degree of counter-irritation in cases where the subject is suffering the first attack of tendinitis.

As has been indicated, ample time should be allowed for recovery and depending upon conditions, it takes from three weeks to six months for complete recovery to become established.

Chronic Tendinitis and Contraction of the Flexor Tendons.

Etiology and Occurrence.--Acute inflammation of the flexor tendons may result in chronic tendinitis. Recurrent attacks in cases where insufficient time is allowed for complete recovery to result, is followed by chronic inflammation and hypertrophy of the tendons. Again, in subjects where conformation is faulty, no amount of care will be sufficient to prevent a recurrence of the inflammation and the condition must become chronic.

Symptomatology.--On visual examination of the subject at rest, one may note the hypertrophied condition of the affected tendons. Their transverse diameter is usually perceptibly increased and in many cases, there is an increase in the antero-posterior diameter. The latter condition causes a bulging of the tendon that is so noticeable, because of the convexity thus formed, it is commonly known as "bowed tendon."

In chronic tendinitis there occurs repeated attacks of inflammation wherein lameness is pronounced and there exists in reality, at such times, acute inflammation of a hypertrophic structure, where at no time does inflammation completely subside. Therefore, in chronic tendinitis there is to be found at times the same conditions which characterize acute inflammation, except that there is usually a variance of symptoms because of the difference in the degree of inflammation and pain.

The diagnosis of contraction of tendons is an easy matter because of the fact that relations between the phalanges are constantly changed with tendinous contraction. If one bears in mind the attachments and function of the digital flexors, no difficulty is encountered in recognizing contraction of either tendon.

Contraction of the superficial digital flexor (perforatus), when uncomplicated, is characterized by volar flexion of the pastern joint. The foot is flat on the ground and the heel is not raised because the superficial flexor tendon does not have its insertion to the distal phalanx (os pedis) and therefore can not affect the position of the foot.

By causing the subject to stand on the affected member, one may outline the course of the flexor tendons by palpation, and in this way recognize any lack of tenseness or contraction of tendons or of the suspensory ligament.

Contraction of the suspensory ligament would cause the pastern joint to assume the same position as is occasioned by contraction of the superficial digital flexor (perforatus) tendon, but when the subject is bearing weight on the affected member, it is easy to determine that no contraction of the suspensory ligament exists, by noting an absence of abnormal tenseness of this structure. And finally, contraction of the suspensory ligament is of rare occurrence.

Contraction of the deep flexor tendon (perforans) causes an elevation of the heel. The foot can not set flat because the insertion of the deep flexor tendon to the solar surface of the distal phalanx (os pedis) causes when the tendon is contracted--a rotation of the distal phalanx on its transverse axis--hence the raised heel. No other tendon has this same effect on the distal phalanx and the condition is correctly diagnosed without difficulty.

Course and Complications.--This condition may exist for years without causing the subject any serious inconvenience, if the affected animal is kept at suitable work. In other instances recurrent attacks of lameness are of such frequent occurrence that the subject is not fit for service. Many affected animals that are kept in service in spite of lameness (and in some instances where no lameness is present), soon become unserviceable because of contraction of the inflamed tendon. This, in fact, is the condition which eventually becomes established in most instances.

Treatment.--Where conformation is not too faulty so that recovery may be expected, good results are obtained by line-firing the tendons and allowing the subject a few months' rest. In some cases median neurectomy is advisable. This is recommended by Breton[25] as being productive of good results even where contraction of tendons exists and tenotomy is done.

By shoeing with high heel-calks considerable strain is taken from the inflamed tendons because of the changed position of the foot which alters the distribution of weight on different parts of the leg. Rubber pads materially diminish concussion and should be made use of when the subject is returned to work, if the character of the work is such as to occasion much concussion.

It is to be remembered, however, that in sprains there occurs fibrillary fracture of soft structures and time is required for regeneration of tissue which has been injured or destroyed. Absolute rest is necessary where inflammation is acute and in sub-acute or chronic tendinitis avoidance of all work which causes irritation to the affected tendons is imperative.

Where contraction of tendons exists surgical treatment is necessary. No good comes from appliances which are calculated to stretch the affected tendons; in fact, they aggravate the inflamed condition and hasten complete loss of function of the affected member. Where there exists no articular or ligamentous diseases which would defeat the purpose, tenotomy is the only remedy for contracted tendons.

Contracted Tendons of Foals.

Etiology and Occurrence.--This condition is occasionally observed and no positive explanation of the reason for its existence can be given. That mal-position _en utero_ causes the metacarpal bones to develop in length so rapidly that the tendons are too short, is an explanation that is offered. Be that as it may, in breeding sections of the country the general practitioner is obliged to handle these cases and successful methods of treatment are essential even though cause is not removable.

Symptomatology.--The superficial flexor tendon (perforatus) alone, is the one usually contracted, and while both flexors are at times involved, this rarely occurs. The condition is usually bilateral.

The degree of contraction varies greatly in different cases. In some, contraction exists to such extent that it is impossible for the colt to stand, and because of continual decubitus where no relief is given, the subject is lost because of gangrenous infection occasioned by bed sores. Otherwise the same symptoms are to be observed in this condition, that exist in contraction of tendons of the mature animal.

Treatment.--Wherever contraction is not too marked and weight is borne with the affected members, and where the feet can be kept on the ground in a nearly normal position, it is possible to correct the condition without doing tenotomy. That is, in cases where the subject is simply "cock-ankled", where volar flexion of the pastern joint exists but the foot is kept flat on the ground, correction is possible without tenotomy.

In such instances the foal must be treated early--before the skin on the anterior pastern region has been badly damaged by knuckling over. It is possible in many cases to stretch the flexor tendons by grasping the colt's foot with one hand, and with the other hand one may push the pastern in the direction of dorsal flexion. This may be tried and when a reasonable amount of force is employed, no harm is done, even though no material benefit results. Some veterinarians claim good results from this treatment alone and direct their clients to repeat the stretching process several times daily.

Whether the tendons are manually stretched or not, splints should be adjusted to the affected members. The legs are padded with cotton and bandages and a suitable splint is applied on either side of the members and securely fixed in position by bandaging.

The splints are kept in position for four or five days and then removed for inspection of the affected parts. If necessary, they are reapplied and left in position for a week; however, this is unnecessary in the average case that is treated in this manner.

Where contraction exists to the extent that the subject can not stand and where no weight is borne by the feet, it is necessary to divide the affected tendons surgically. The same technic is put into practice that is employed in the mature subject but there is much greater chance for a favorable outcome in the foal. Further, if necessary, one may divide with impunity, both tendons on each leg, at the same time. In all cases this operation is done by observing strict aseptic precautions and the legs are, of course, bandaged. If both tendons are divided, splints should be employed and kept in position for ten days or two weeks. Primary union of the small surgical wound of the skin and fascia occurs in forty-eight hours.

The reader is referred to William's "Veterinary Surgical and Obstetrical Operations," for a complete description of this operation.

In veterinary literature there is occasionally described a condition which affects young foals wherein symptoms similar to those of contraction of the flexors are manifested, but upon examination it is found that rupture of the extensor of the digit (extensor pedis) exists. This affection is briefly described by Cadiot but no complete treatise on this condition has been published.

In parts of Canada foals of from one to three days of age are found affected in such manner that more or less interference with the gait is to be seen in those moderately affected. There is, in some subjects, only a slight impediment in locomotion which is occasioned by inability to properly extend the digit. In other subjects, while able to stand and walk, great difficulty is experienced because of volar flexion of the phalanges. The more seriously affected animals are unable to stand and, in most instances, perish because of the effects of prolonged decubitus.

A local enlargement occurs at the anterior carpal region and the mass is somewhat fluctuating, extravasated fluids becoming infected in many instances, and necrosis of the skin and fascia provide means for spontaneous discharge of the contents of the enlargement if it is not opened. The infection when it becomes generalized causes a fatal termination in most cases that are not treated.

Native stock owners of some parts of Canada know this condition as "fish knees" because of the presence of the ruptured end of the extensor tendon which is found coiled in the cavity of the enlargements caused by the ruptured tendon.

Local practitioners have treated the condition by incising the swollen mass and removing the part of tendon contained within such cavities. Treatment has not proved entirely satisfactory in the majority of instances, perhaps because of tardy interference.

In a colt's leg sent the author by Mr. Thomas Millar, M.R.C.V.S., of Asquith, Saskatchewan, a careful dissection of the carpal region revealed the fact that in this case the ruptured extensor tendon was due to injury. The colt may have been trampled upon by its dam in such manner that the tendon was divided. No noticeable evidence of injury to the skin was to be seen on its outer surface, but on the fascial side a cyanotic congested area, which was situated immediately over the site of the ruptured tendon, was very evident.

With the execution of a good surgical technic, the ruptured tendon might be sutured; the wound of the tendon sheath as well as that of the skin carefully united by means of gut sutures, the leg bandaged and immobilized with leather splints and recovery follow in a reasonable percentage of cases so treated. These cases afford an opportunity for the perfection of practical means of treatment by those who frequently meet with this affection.

Rupture of the Flexor Tendons and Suspensory Ligament.

Etiology and Occurrence.--Rupture of the flexor tendons or of the suspensory ligament is of rare occurrence. Frequently, these structures are divided as the result of wounds; but rupture, due to strain, is not frequent.

In some cases in running horses, or in animals that are put to strenuous performances, such as are jumpers, rupture of tendons or of the suspensory ligament takes place. However, more frequently this follows certain debilitating diseases such as influenza or local infectious inflammation of the parts which results in degenerative changes and rupture follows.

The non-elastic suspensory ligament receives some heavy strains during certain attitudes which are taken by horses in hurdle jumping as is explained in detail by Montané and Bourdelle[26] under the description of this ligament. But in spite of the frequent and unusually heavy strains, which these structures receive, complete rupture is not frequently seen.

Symptomatology.--When the anatomy and function of the flexor tendons and suspensory ligament is thoroughly understood, recognition of rupture of either of these structures is easily recognized. When one considers that in rupture, a position directly opposite to that which is seen in contraction in either one of these structures, is assumed, a detailed description of each separate condition is needless repetition.

However, it is pertinent to suggest that rupture of the deep flexor tendon (perforans) allows a turning up of the toe. Whether it be torn loose from its point of attachment or ruptured at some point proximal thereto, the position is the same--heel flat on the ground, toe slightly raised and this raising of the toe varies in degree as the subject moves about.

When the superficial flexor (perforatus) is ruptured there is no change in the position of the foot but the fetlock joint is slightly lowered. The pathognomonic symptom is the lax tendon during weight bearing, which may be felt by palpation of the tendon along its course in the metacarpal region.

With complete rupture of the suspensory ligament there occurs a marked dropping of the fetlock joint and an abnormal amount of weight is then thrown upon the superficial flexor tendon (perforatus), causing it to be markedly tensed. This is readily recognized by palpation. By palpating the suspensory ligament from its proximal portion down to and beyond its bifurcation, while the affected member is supporting weight, it is possible to diagnose rupture of one of its branches.

Prognosis and Treatment.--In rupture of the superficial flexor tendon (perforatus) because of its comparatively less important function, prognosis is favorable and recovery takes place when proper treatment is put into practice.

With rupture of the deep flexor tendon (perforans), especially when it occurs at or near its point of insertion and sometimes following disease, prognosis is unfavorable.

Rupture of the suspensory ligament constitutes a condition which is, as a rule, hopeless, because of the impracticability of treating such cases.

The salient feature which characterizes any practical attempt at treatment of ruptured tendons or other portions of the inhibitory apparatus of the fetlock region, is to retain the phalanges in their normal position for a sufficient length of time that the approximated ends of ruptured tendons or ligaments may unite. The length of time required for this to occur, together with the difficulties encountered in confining the affected extremities in suitable braces or supportive appliances, precludes all possibility of this condition's being practically amenable to treatment when the deep flexor tendon (perforans) and suspensory ligament are simultaneously ruptured. It does not follow, even so, that recovery does not succeed treatment in some of these unfavorable cases.

Affected subjects are kept in slings as long as it seems necessary--until they learn to get up without deranging the braces worn.

Several styles of braces are in use and each has its objections; nevertheless some sort of support to the affected member is necessary and steel braces which are connected with shoes are usually employed.

The principal difficulty which attends the use of braces is pressure-necrosis of the skin which is caused by the constant and firm contact of the metal support. The practitioner's ingenuity is taxed in every case to contrive practical means of padding the exposed parts in order to prevent or minimize necrosis from pressure. This is attempted--with more or less success--by frequent changing of bandages and the local application of such agents as alcohol or witch hazel. Needless to say, the skin must be kept perfectly clean and the dressings free from all irritating substances.

The fact that tendons or ligaments which are ruptured, do not regenerate as readily as in cases where traumatic or surgical division occurs, must not be lost sight of, and prognosis is given in accordance.

Thecitis and Bursitis in the Fetlock Region.