Lameness of the Horse Part 12

Before there is evidence of an exostosis, diagnosis of ringbone is not easy, for it is then a problem of detecting the presence of a ligamentous sprain, periost.i.tis, or osteitis. The diagnostician should take note of local manifestations of hypersensitiveness, or heat if such exist, and, in addition, other conditions must be excluded before definite conclusions are possible.

In _articular_ ringbone as soon as there is developed an exostosis, it occupies a position on the dorsal (anterior) part of the articulation and extends around the sides of the joint.

_Periarticular_ ringbone is characterized by exostoses which are situated on the sides of the phalanges and not extending around to the anterior part of the joint. This type of ringbone as well as the articular may occur "high" or "low."

[Ill.u.s.tration: Fig. 19--Phalangeal exostoses in chronic ringbone. Museum specimen of the Kansas City Veterinary College.]

With the _traumatic_ form of ringbone, all consequences, as to the size and form the exostosis is to a.s.sume, depend upon the nature and extent of the injury.

_Rachitic_ ringbone is frequently observed in some sections of the country and does not ordinarily cause much if any lameness. It is a disease of colts and may affect one or all of the phalanges at the same time. As the subject advances in age there is more or less diminution in the size of the enlargements.

Treatment.--Rest is essential in the treatment of ringbone. If diagnosed during its incipiency, remedial measures such as are usually employed to treat sprains, are indicated and later the parts should be blistered. When an exostosis has developed puncture firing is the remedy _par excellence_. Not that this method of treatment is infallible, for to any thinking one who takes into consideration the pathological anatomy of this condition, it is evident that no manner of treatment is beneficial in some cases. If the exostosis is so situated that it does not mechanically interfere with function, and is not so large that it may inhibit flexion and extension, and where the articular portions of the joint are not eroded, good results attend the use of the actual cautery.

In firing, after having anesthetized the extremity, and prepared the surgical area, the cautery is deeply inserted in numerous places, taking care, however, not to open the joint. The parts are immediately covered with aseptic absorbent cotton and this dressing is left in position for forty-eight hours and if perchance there is evidence of synovial discharge, the parts are again aseptically dressed in order to prevent infection of the articulation. If, as is the case usually, no perforation of the joint capsule exists, the openings made by the cautery have been closed by the coagulation of serum and there is then little chance of infection causing trouble, even though the member is left unbandaged.

In several instances, the author has treated ringbone by this method where the periarticular type existed and lameness was marked, and in three weeks the subjects were in service and not lame--this, in one instance in a valuable polo pony where the subject continued in service for more than a year without any evidence of recurrence of the lameness.

The production of a deep-seated and acute inflammation with the actual cautery is preferable to any sort of counter-irritation which may be produced by vesicants.

There is no occasion for any difference in the treatment of either of the first three cla.s.ses of ringbone, but in the rachitic type where treatment is given, the application of a vesicant is all that is required. In most instances treatment is not necessary.

The affected animals require a month to three months' time for recovery to take place in the average favorable cases of ringbone.

Median neurectomy is of service in many instances where lameness is not completely relieved by the use of the actual cautery and no bad results attend the performance of this operation even though no benefit is derived thereby. Plantar neurectomy is contraindicated in all cases where there exists much lameness. If lameness is due to acute inflammation bad results such as sloughing and loss of the hoof may follow; and if large exostoses mechanically interfere with function of the joint, or where articular erosions exist, no possible good can come from neurectomy. Careful discrimination should be employed in selecting cases for neurectomy for this operation; otherwise, it is very likely to prove disappointing.

Open Sheath of the Flexors of the Phalanges.

This condition does not differ from a like affection involving other tendons except that the function of these tendons is such that large synovial sheaths are necessary, and when synovitis exists, the condition then becomes more serious.

Infectious synovitis involving these tendons in the fetlock region is of more frequent occurrence than a like affection of carpal or tarsal sheaths. With the exception of the extent of the involvement and distress occasioned thereby, synovitis the result of open tendon sheaths, is similar wherever it occurs.

Etiology.--The same conditions which are responsible for open fetlock joint and other wounds of the pastern region, cause open tendon sheaths of the flexor tendons.

Symptomatology.--Because of the size and extent of this sheath and the different manner in which it is opened, there is manifested dissimilar symptoms in different cases. A nail puncture which perforates the sheath in the pastern region and at the same time produces an infectious synovitis, will cause a markedly different manifestation than will a wound which freely opens the sheath above the fetlock. In the first instance, the condition is much more painful; swelling is intense in some cases; and if the subject does not possess sufficient resistance so that spontaneous resolution promptly occurs, surgical evacuation of pus is usually necessary. When these tendon sheaths are opened, there follows a reaction which is quite a.n.a.logous to that which exists in arthritic synovitis, but instead of ankylosis, adhesions with thecal obliteration occur. Rarely there result cartilaginous and osseous formations.

The const.i.tutional disturbances which characterize this condition vary with the degree of distress occasioned. As the infection is virulent and causes serious destruction of the affected parts, so does evidence of malaise and finally distress appear. Detailed discussions of symptomatology in similar conditions have heretofore been given, and further repet.i.tion is unnecessary.

Treatment.--The same general plan of treatment which is employed for handling open joint is put in practice in these cases. Following the preoperative cleansing of the external wound and adjacent surfaces, where liberal drainage exists, tincture of iodin is injected into the sheath, the parts covered with a suitable dressing powder, and the entire member is carefully dressed with cotton and bandages.

Subsequent treatment is the same as has been outlined in the discussion of open fetlock joint on page 112. The same general plan of after-care is necessary. Recovery, however, does not require so much time ordinarily, yet punctures of the sheath occasioned by nails or other small implements make for long drawn out cases of infective synovitis.

Luxation of the Fetlock Joint.

Etiology and Occurrence.--The manner of construction of the fetlock joint is such that disarticulation without irreparable injury resulting, is practically impossible. Logically, this joint in the fore legs (not so in the pelvic limbs) should disarticulate in such manner that either all of the inhibitory apparatus (flexor tendons and suspensory ligament) must rupture or a lateral luxation is necessary. Lateral disarticulation must necessarily sever the attachment of one of the common collateral ligaments. Because of the width (transverse diameter) of the articulating surfaces of this joint, lateral luxation requires a great strain; and a force that is sufficient to occasion this trauma usually causes serious additional injury. Therefore, the condition is considered one wherein prognosis is always unfavorable in so far as practical methods of treatment are concerned.

Mr. A. Barbier[22] reports a case of bilateral luxation of the fetlock joints of the hind legs in a horse. This was done in jumping, and the extensor tendon of each leg was ruptured and the anterior portion of the metatarsus was protruding through the skin. Profuse hemorrhage had taken place due to tearing of the blood vessels.

Symptomatology.--Entire luxation of this joint when present is so evident that one cannot fail to recognize the condition. Complete disarrangement of normal relation occurs and there is either a breaking down of the inhibitory apparatus, or if a lateral disarticulation exists, the normally straight line formed by the bones of the front leg, as viewed from the front or rear, is broken at the fetlock.

Often fracture of bones are concomitant and then, of course, mobility is increased and not decreased as is the case in uncomplicated luxation.

Such violence occurs at times, when this joint is disarticulated, that the joint capsule is also completely ruptured and the articular portion of the bones is exposed to view.

Treatment.--The condition being practically a hopeless one, destruction of the subject is the thing which should be promptly done.

In valuable breeding animals, owners may prefer that treatment be attempted when a lateral luxation and detachment of but one common ligament have permitted luxation without complete disarticulation and rupture of the joint capsule. In such cases, by immobilizing the affected parts as in fracture, and confining the subject in a sling for about sixty days, partial recovery may occur in some instances.

Experience has shown that where luxation with detachment of a collateral ligament occurs, recovery is slow and incomplete--there always results considerable exostosis at the site of injury.

Sesamoiditis.

Etiology and Occurrence.--Inflammation of the proximal sesamoid bones is caused by any kind of irritation which may involve this part of the inhibitory apparatus. Positioned as they are, between the bifurcations of the suspensory ligament and the pastern joint, they serve as fulcra and effectively a.s.sist in minimizing concussion which is received by the suspensory ligament. The flexor tendons also, in contracting, exert strain upon the inter-sesamoidean ligament, which has a similar effect upon the sesamoid bones as that which is produced by the suspensory ligament.

The condition occurs quite frequently, and because of the important function performed by these bones, active inflammation of the sesamoids const.i.tutes a serious affection. Because of the fact that these bones have proportionately large articular surfaces, when they are inflamed to the extent that degenerative changes affect the articular cartilage, complete recovery seldom results.

The same pathological changes occur here that are to be seen in any case of arthritis. No special pathological condition characterizes sesamoiditis but this condition causes incurable lameness when the sesamoid bones are much inflamed.

Symptomatology.--In acute inflammation, there exist all the symptoms which portray any arthritic inflammation of like character. The parts are readily palpable and are found to be hot, supersensitive, and more or less infiltration of the tissues contiguous to the joint causes swelling. There is volar flexion of the phalanges when the subject is at rest. Lameness is intense; in some acute inflammatory disturbances the subject is unable to bear weight on the affected member.

In chronic sesamoiditis, constant lameness is the one salient feature which marks the condition. While it is possible for one sesamoid bone to become involved without its fellow being affected, this is not usual.

Considerable organization of tissue surrounding the joint is present and no particular evidence of supersensitiveness exists. However, supporting weight brings sufficient pressure to bear upon the inflamed and more or less eroded bones so that pain is occasioned and lameness results.

Treatment.--During acute inflammation, absolute quiet is, of course, of first consideration. Cold packs are to be kept in contact with the parts until acute inflammatory symptoms subside. The fetlock region is then enveloped with a poultice or an iodin and glycerin combination (iodin one part to seven parts of glycerin) is applied and a dressing of cotton is kept in contact with the inflamed region. Following this, a vesicant is employed and the subject is allowed a month's rest.

In sub-acute cases, the entire region surrounding the pastern is blistered or the actual cautery is used. Line-firing is preferable. The subject is given a month or six weeks rest and one may be guided by the presence or absence of lameness as to whether improvement or recovery is taking place.

Old chronic cases, and particularly those where there are considerable induration and fibrous organization of tissue surrounding the joint, are not to be benefited by treatment.

The chief consideration in handling sesamoiditis is checking inflammation as early as possible and preventing, if this can be done, the erosion of articular surfaces. If destruction of any part of the articular surfaces can be prevented and the patient allowed ample time for complete resolution of the affected parts to occur, permanent relief is possible.

Fracture of the Proximal Sesamoids.

Etiology and Occurrence.--Fracture of the proximal sesamoid bones is caused by violent strain when there exists _fragilitas osseum_, or by contusions. The author treated a case where fracture of one sesamoid was occasioned by a horse receiving a puncture wound wherein the sharp end of a steel bar was protruding from the ground where it was firmly embedded. The subject in this case was injured while being driven along a country road. Frost[23] reports simultaneous fracture of all of the proximal sesamoids occurring in a sixteen-year-old pony. The condition is of rather common occurrence in some countries because of the fragile condition of horses' bones.

Symptomatology.--If the parts can be examined before extravasation of blood and swelling mask the condition, crepitation may be detected. In other instances, it is possible to note a displacement of parts of the sesamoid bones--this in horizontal fracture. There occurs more or less descent of the fetlock which must not be attributed to rupture of the superficial flexor tendon (perforatus). By outlining the course of this tendon with the fingers, when it is pa.s.sively tensed sufficiently to follow its course, one may exclude rupture of the superficial flexor.

Finding the suspensory ligament intact from its origin to the sesamoid attachments, one may also eliminate rupture of this structure as a cause of the trouble. Needless to say, marked lameness and swelling of the fetlock soon take place. The condition is painful, and ordinarily, recovery is impossible.

Treatment.--Where treatment is attempted, immobilization as in luxation is in order. The patient's comfort is sought, and if the fractured parts can be kept in close proximity, their union may occur in time. However, chances for partial recovery (which is the best to be hoped for) are so remote that early destruction of the subject is the humane and economical thing to do.

Where treatment is inst.i.tuted, it is found that there is required a long time for union of the fractured bones to occur (where union does take place) and the cost of treatment together with the uncertainty of even partial recovery, makes for an unfavorable outcome. When the best possible results succeed treatment, a large callosity is formed and movement of the pastern joint is restricted. Lameness, though not intense, in the case referred to, where one bone was broken, was permanent and the subject was out of service for nearly a year.

Inflammation of the Posterior Ligaments of the Pastern (Proximal Interphalangeal) Joint.

Anatomy.--The ligaments here involved are the four volar ligaments described by Sisson[24] as follows: "The _volar ligaments_ (Ligg Volaria) consist of a central pair and a lateral and medial bands which are attached below to the posterior margin of the proximal end of the second phalanx and its complementary fibro-cartilage. The lateral and medial ligaments are attached above to the middle of the borders of the first phalanx, the central pair lower down and on the margin of the triangular rough area."

This portion of the inhibitory apparatus is described by Strangeways'