Chapter 38

As with sidebones, though for a somewhat different reason, the dimensions of the spavin and the degree of the lameness do not seem to bear any determinate relation, the most pronounced symptoms at times accompanying a very diminutive growth. The distinction between the two varieties of cool and warm, however, may easily be determined by remembering the fact that in most cases the first, or cool, is due to a simple exostosis, while the second is generally connected with disease of the articulation, such as ulceration of the articular surface--a condition which, as we proceed further, will receive our attention when we reach the subject of stringhalt.

An excellent test for spavin lameness, which may be readily applied, consists in lifting the affected leg from the ground for one or two minutes and holding the foot high so as to flex all the joints. An assistant, with the halter strap in his hand, quickly starts the animal off in a trot, when, if the hock joint is affected, the lameness will be so greatly intensified as to lead readily to a diagnosis.

_Prognosis._--Having thus fully considered the history of bone spavin, we are prepared to give due weight to the reasons that exist for the adverse prognosis which we must usually feel compelled to pronounce when encountering it in practice, as well as to realize the importance of early discovery. It is but seldom, however, that the necessary advantage of this early knowledge can be obtained, and when the true nature of the trouble has become apparent it is usually too late to resort to the remedial measures which, if duly forewarned, a skillful practitioner might have employed. We are fully persuaded that but for the loss of the time wasted in the treatment of purely imaginary ailments very many cases of bone spavin might be arrested in their incipiency and their victims preserved for years of comfort for themselves and valuable labor to their owners.

_Treatment._--To consider a hypothetical case: An early discovery of lameness has been made; that is, the existence of an acute inflammation--of periostitis--has been detected. The increased temperature of the parts has been observed, with the stiffened gait and the characteristic pose of the limb, and the question is proposed for solution, What is to be done? Even with only these comparatively doubtful symptoms--doubtful with the nonexpert--we should direct our treatment to the hock in preference to any other joint, since of all the joints of the hind leg it is this which is most liable to be attacked, a natural result from its peculiarities of structure and function. And in answer to the query, What is the first treatment indicated? We should answer _rest_--emphatically, and as an essential condition, _rest_. Whether only threatened, suspected, or positively diseased, the animal must be wholly released from labor, and it must be no partial or temporary quiet of a few days. In all stages and conditions of the disease, whether the spavin is nothing more than a simple exostosis, or whether accompanied with the complication of arthritis, there must be a total suspension of effort until the danger is over. Less than a month's quiet ought not to be thought of--the longer the better.

Good results may also be expected from local applications. The various lotions which cool the parts, the astringents which lower the tension of the blood vessels, the tepid fomentations which accelerate the circulation in the engorged capillaries, the liniments of various composition, the stimulants, the opiate anodynes, the sedative preparations of aconite, the alterative frictions of iodin--all these are recommended and prescribed by one or another. We prefer counterirritants, for the reason, among many others, that by the promptness of their action they tend to prevent the formation of the bony deposits. The lameness will often yield to the blistering action of cantharides, in the form of ointment or liniment, and to the alterative preparations of iodin or mercury. If the owner of a "spavined" horse really succeeds in removing the lameness, he has accomplished all that he is justified in hoping for; beyond this let him be well persuaded that a "cure" is impossible.

For this reason, moreover, he will do well to be on his guard against the patented "cures" which the traveling horse doctor may urge upon him, and withhold his faith from the circular of the agent who will deluge him with references and certificates. It is possible that nostrums may in some exceptional instances prove serviceable, but the greater number of them are capable of producing only injurious effects. The removal of the bony tumor can not be accomplished by any such means, and if a trial of these unknown compounds should be followed by complications no worse than the establishment of one or more ugly, hairless cicatrices, it will be well for both the horse and his owner.

Rest and counterirritation, with the proper medicaments, constitute, then, the prominent points in the treatment designed for the relief of bone spavin. Yet there are cases in which all the agencies and methods referred to seem to lack effectiveness and fail to produce satisfactory results. Either the rest has been prematurely interrupted or the blisters have failed to modify the serous infiltration, or the case in hand has some undiscernible characteristics which seem to have rendered the disease neutral to the agencies used against it. An indication of more energetic means is then presented, and free cauterization with the firing iron becomes necessary.

At this point a word of explanation in reference to this operation of firing may be appropriate for the satisfaction of any among our readers who may entertain an exaggerated idea of its severity and possible cruelty.

The operation is one of simplicity, but is nevertheless one which, in order to secure its benefits, must be reserved for times and occasions of which only the best knowledge and highest discretion should be allowed to judge. It is not the mere application of a hot iron to a given part of the body which constitutes the operation of firing. It is the methodical and scientific introduction of heat into the structure with a view to a given effect upon a diseased organ or tissue by an expert surgeon. The first is one of the degrees of mere burning. The other is scientific cauterization, and is a surgical manipulation which should be committed exclusively to the practiced hand of the veterinary surgeon.

Either firing alone or stimulation with blisters is of great efficacy for the relief of lameness from bone spavin. Failure to produce relief after a few applications and after allowing a sufficient interval of rest should be followed by a second or, if needed, a third firing.

In case of further failure there is a reserve of certain special operations which have been tried and recommended, among which those of cunean tenotomy, periosteotomy, the division of nervous branches, etc., may be mentioned. These, however, belong to the peculiar domain of the veterinary practitioner, and need not now engage our attention.

FRACTURES.

In technical language a fracture is a "solution of continuity in the structure or substance of a bone." It ranks among the most serious of the lesions to which the horse--or any animal--can be subject. It is a subject of special interest to veterinarians and horse owners in view of the fact that it occurs in such a variety of forms and subjects the patient to much loss of time, resulting in the suspension of his earning capacity. Though of less serious consequence in the horse than in man, it is always a matter of grave import. It is always slow and tedious in healing and is frequently of doubtful and unsatisfactory result.

This solution of continuity may take place in two principal ways. In the most numerous instances it includes the total thickness of the bone and is a complete fracture. In other cases it involves only a portion of the thickness of the bone, and for that reason is described as incomplete. If the bone is divided into two separate portions and the soft parts have received no injury, the fracture is a simple one, or it becomes compound if the soft parts have suffered laceration, and comminuted if the bones have been crushed or ground into fragments, many or few. The direction of the break also determines its further classification. Broken at a right angle, it is transverse; at a different angle it becomes oblique, and it may be longitudinal or lengthwise. In a complete fracture, especially of the oblique kind, there is a condition of great importance in respect to its effect upon the ultimate result of the treatment in the fact that from various causes, such as muscular contractions or excessive motion, the bony fragments do not maintain their mutual coaptation, but become separated at the ends, which makes it necessary to add another descriptive term--with displacement. These words again suggest the negative and introduce the term without displacement, when the facts justify that description. Furthermore, a fracture may be intra-articular or extra-articular, as it extends into a joint or otherwise, and, once more, intra-periosteal when the periosteum remains intact. Finally, there is no absolute limit to the use of descriptive terminology in the case.

The condition of displacement is largely influential in determining the question of treatment and as affecting the final result of a case of fracture. This, however, is dependent upon its location or whether its seat is in one or more of the axes of the bone, in its length, its breadth, its thickness, or its circumference. An incomplete fracture may also be either simple or comminuted. In the latter case the fragments are held together by the periosteum when it is intact; in that case the fracture belongs to the intra-periosteal class. At times, also, there is only a simple fissure or split in the bone, making a condition of much difficulty of diagnosis.

_Causes._--Two varieties of originating cause may be recognized in cases of fracture. They are the predisposing and the occasional. As to the first, different species of animals differ in the degree of their liability. That of the dog is greater than that of the horse, and in horses the various questions of age, the mode of labor, the season of the year, the portion of the body most exposed, and the existence of ailments, local and general, are all to be taken into account.

Among horses, those employed in heavy draft work or that are driven over bad roads are more exposed than light-draft or saddle horses, and animals of different ages are not equally liable. Dogs and young horses, with those which have become sufficiently aged for their bones to have acquired an enhanced degree of frangibility, are more liable than those which have not exceeded the time of their prime. The season of the year is undoubtedly, though in an incidental way, an important factor in the problem of the etiology of these accidents, for though they may be observed at all times, it is during the months when the slippery condition of the icy roads renders it difficult for both men and beasts to keep their feet that they occur most frequently. The long bones, those especially which belong to the extremities, are most frequently the seat of fractures, from the circumstance of their superficial position, their exposure to contact and collision, and the violent muscular efforts involved both in their constant, rapid movement and their labor in the shafts or at the pole of heavy and heavily laden carriages.

The relation between sundry idiosyncrasies and diathesis and a liability to fractures is too constant and well-established a pathological fact to need more than a passing reference. The history of rachitis, of melanosis, and of osteoporosis, as related to an abnormal frangibility of the bones, is a part of our common medical knowledge. There are few persons who have not known of cases among their friends of frequent and almost spontaneous fractures, or at least of such as seem to be produced by the slightest and most inadequate violence, and there is no tangible reason for doubting an analogous condition in dividuals of the equine race. Among local predisposing causes mention must not be omitted of such bony diseases as caries, tuberculosis, and others of the same class.

Exciting, occasional, or "efficient" causes of fracture are in most instances external traumatisms, as violent contacts, collisions, falls, etc., or sudden muscular contractions. These external accidents are various in their character, and are usually associated with quick muscular exertion. A violent, ineffectual effort to move too heavy a load; a semispasmodic bracing of the frame to avoid a fall or resist a pressure; a quick jump to escape a blow; stopping too suddenly after speeding; struggling to liberate a foot from a rail, perhaps to be thrown in the effort--all these are familiar and easy examples of accidents happening hourly by which our equine servants become sufferers. We may add to these the fracture of the bones of the vertebræ, occurring when casting a patient for the purpose of undergoing a surgical operation, quite as much as the result of muscular contraction as of a preexisting diseased condition of the bones. A fracture occurring under these circumstances may be called with propriety indirect, while one which has resulted from a blow or a fall differently caused is of the direct kind.

_Symptoms._--We now return to the first items in our classification of the varieties of fractures for the purpose of bringing them in turn under an orderly review, and our first examination will include those which belong to the first category, or the complete kind. Irregularity in the performance of the functions of the apparatus to which the fractured bone belongs is a necessary consequence of the existing lesion, and this is lameness. If the broken bone belongs to one of the extremities, the impossibility of the performance of its natural function in sustaining the weight of the body and contributing to the act of locomotion is usually complete, though the degree of disability will vary according to the kind of fracture and the bone which is injured. For example, a fracture of the cannon bone without displacement, or of one of the phalanges, which are surrounded and sustained by a complex fibrous structure, is, in a certain degree, not incompatible with some amount of resting on the foot. On the contrary, if the shank bone, or that of the forearm is the implicated member, it would be very difficult for the leg to exercise any agency whatever in the support of the body, and in a fracture of the lower jaw it would be obviously unreasonable to expect it to contribute materially to the mastication of feed.

It seldom happens that a fracture is not accompanied with a degree of deformity, greater or less, of the region or the leg affected. This is due to the exudation of the blood into the meshes of the surrounding tissues and to the displacement which occurs between the fragments of the bones, with subsequently the swelling which follows the inflammation of the surrounding tissues. The character of the deformity will mainly depend upon the manner in which the displacement occurs.

In a normal state of things the legs perform their movements with the joints as their only centers or bases of action, with no participation of intermediate points, while with a fracture the flexibility and motion which will be observed at unnatural points are among the most strongly characteristic signs of the lesion. No one need be told that, when the shaft of a limb is seen to bend midway between the joints, with the lower portion swinging freely, the leg is broken. There are still some conditions, however, in which the excessive mobility is not easy to detect. Such are the cases in which the fracture exists in a short bone, near a movable joint, or in a bone of a region where several short and small bones are united in a group, or even in a long bone the situation of which is such that the muscular covering prevents the visible manifestation of the symptom.

If the situation of a fracture precludes its discovery by means of this abnormal flexibility, other modes of detection remain. There is one method which is absolute and positive and which can be applied in by far the most, though not in all cases. This is crepitation, or the peculiar effect which is produced by the friction of the fractured surfaces one against another. Though discerned by the organs of hearing it can scarcely be called a sound, for the grating of the parts as the rubbing takes place is more felt than heard; however, there is no mistaking its import in cases favorable for the application of the test. The conditions in which it is not available are those of incomplete fracture, in which the mobility of the part is lacking, and those in which the whole array of phenomena are usually obscure. To obtain the benefit of this pathognomonic sign requires deliberate, careful, and gentle manipulation. Sometimes the slightest of movements will be sufficient for its development, after much rougher handling has failed to discover it. Perhaps the failure in the latter case is due to a sort of defensive spasmodic rigidity caused by the pain resulting from the rude interference.

More or less reactive fever is a usual accompaniment of a fracture. Ecchymosis in the parts is but a natural occurrence, and is more easily discovered in animals possessing a light-colored and delicate skin than in those of any other character.

There are difficulties in the way of the diagnosis of an incomplete fracture, even sometimes when there is a degree of impairment in the function of locomotion, with evidences of pain and swelling at the seat of lesion. There should then be a careful examination for evidences of a blow or other violence sufficient to account for the fracture, though very often a suspicion of its existence can be converted into a certainty only by a minute history of the patient if it can be obtained up to the moment of the occurrence of the injury. A diagnosis ought not to be hastily pronounced, and where good ground for suspicion exists it ought not to be rejected upon any evidence less than the best. We too often read of serious and fatal complications following careless conclusions in similar cases, among which we may refer to one instance of a complete fracture manifesting itself in an animal during the act of rising in his stall after a decision had been pronounced that he had no fracture at all.

Fractures are of course liable to complications, especially those which are of a traumatic character, such as extensive lacerations, tearing of tissues, punctures, contusions, etc. Unless these are in communication with the fracture itself the indication is to treat them simply as independent lesions upon other parts of the body. A traumatic emphysema at times causes trouble, and abscesses, more or less deep and diffused, may follow. In some cases small, bony fragments from a comminuted fracture, becoming loose and acting as foreign bodies, give rise to troublesome fistulous tracts. A frequent complication is hemorrhage, which often becomes of serious consequence. A fracture in close proximity to a joint may be accompanied with dangerous inflammations of important organs, and induce an attack of pneumonia, pleurisy, arthritis, etc., especially if near the chest; it may also cause luxations, or dislocations. Gangrene, as a consequence of contusions or of hemorrhage or of an impediment to the circulation, caused by unskillfully applied apparatus, must not be overlooked among the occasional incidents; nor must lockjaw, which is not an uncommon occurrence. Even founder, or laminitis, has been met with as the result of forced and long-continued immobility of the feet in the standing posture, as one of the involvements of unavoidably protracted treatment.

When a simple fracture has been properly treated and the broken ends of the bone have been securely held in coaptation, one of two things will occur. Either--and this is the more common event--there will be a union of the two ends by a solid cicatrix, the callus, or the ends will continue separated or become only partially united by an intermediate fibrous structure. In the first instance the fracture is consolidated or united; in the second there is a false articulation, or pseudarthrosis.

The time required for a firm union or true consolidation of a fracture varies with the character of the bone affected, the age and constitution of the patient, and the general conditions of the case. The union will be perfected earlier in a young than in an adult animal, and sooner in the latter than in the aged, and a general healthy condition is, of course, in every respect, an advantage.

The mode of cicatrization, or method of repair in lesions of the bones, has been a subject of much study among investigators in pathology, and has elicited various expressions of opinion from those high in authority. The weight of evidence and preponderance of opinion are about settled in favor of the theory that the law of reparation is the same for both the hard and the soft tissues. In one case a simple exudation of material, with the proper organization of newly formed tissue, will bring about a union by the first intention, and in another the work will be accompanied with suppuration, or union by the second intention, a process so familiar in the repair of the soft structures by granulation.

Considering the process in its simplest form, in a case in which it advances without interruption or complication to a favorable result, it may probably be correctly described in this wise:

On the occurrence of the injury an effusion of blood takes place between the ends of the bone. The coagulation of the fluid soon follows, and this, after a few days, undergoes absorption. There is then an excess of inflammation in the surrounding structure, which soon spreads to the bony tissue, when a true ostitis is established, and the compact tissue of the bone becomes the seat of a new vascular organization, and of a certain exudation of plastic lymph, appearing between the periosteum and the external surface of the bone, as well as on the inner side of the medullary cavity. After a few days the ends of the bone thus surrounded by this exudate become involved in it, and the lymph, becoming vascular, is soon transformed into cartilaginous, and in due time into bony, tissue.

Thus the time required for the consolidation of the fractured segments is divisible into two distinct periods. In the first they are surrounded by an external bony ring, and the medullary cavity is closed by a bony plug or stopper, constituting the period of the provisional callus. This is followed by the period of permanent callus, during which the process of converting the cartilaginous into the osseous form is going forward.

The restorative process is sooner completed in the carnivorous than in the herbivorous tribes. In the former the temporary callus may attain sufficient fineness of consistency for the careful use of the limb within four weeks, but with the latter a period of from six weeks to two months is not too long to allow before removing the supporting apparatus from the limb.