DISEASES OF THE JOINTS IN HORSES AND OTHER ANIMALS.

New Zealand Times, Volume XXX, Issue 4442, 15 June 1875, Page 3

DISEASES OF THE JOINTS IN HORSES AND OTHER ANIMALS.

DISEASES OF LIGAMENTS. The fibrous bands which are connected with joints are liable to suffer from injuries arising from excessive or unexpected motion of the bones to which they are attached. Ligaments are highly elastic, but they are not extensile, and the immediate effect of the application of a powerful extending force is to inflict a strain upon the fibres from which they are incapable of recovering. In consequence of the injury, the fibrous tissue suffers from irritation, which soon becomes inflammation, with its ordinary symptoms of heat, enlargement, and increased sensibility, and its common result—exudation of fibrinous material, which often becomes so intimately blended with the'ligamentous fibres as to constitute a permanent addition to their structure. It may, however, happen that the inflammatory disease subsides without leaving any permanent deposit, and the ligament is left in a relaxed condition which is incompatible with the due performance of its restraining function. Where bones are loosely articulated, the relaxation of the ligaments permits such extensive motion that the animal loses all control over the limb, and efforts to progress are rendered abortive. Lambs are occasionally liable to suffer from a relaxed condition of the round ligament which connects the head of the thigh bone_ to the bottom of the cavity in the pelvis (acetabulum). This defect allows the thigh bone to slip out of the socket, and gives to the animal a peculiar gait, which is often thought to be the result of partial paralysis, or of rickets. The causes of the relaxation of the round ligament are generally congenital; bad treatment of the ewes during gestation, exposure to cold and wet, and insufficient food, are among the influences which may be presumed to act in causing imperfect development of the tissues of the foetus ; and it is generally observed that the worst eases of relaxation of ligaments occur among weakly lambs. : Very little can be done in the way of special treatment. Restoration of the' proper tone to the system is necessary before any improvement can take place in the local disease. The ewes should have a liberal diet, and be properly sheltered from bad weather ; rock salt should also be put.within reach. Tinder this system of management many of the lambs will recover. The worst cases, however, -will seldom repay the cost and trouble of treatment. The disease is not fatal, but the animals remain in such a miserable plight that there is very little gained in keeping them. A somewhat similar condition to that which results from elongation of the round ligament of the hip joint is seen in some instances in the stifle joint, in that portion of it at least which is formed by the articulation of the patella. As this articulation is less important than the hip joint, the effect on the animal's progression is not so marked ; but, nevertheless, considerable discomfort is occasioned by the frequent slipping of the bone from its position when the animal lies down or rises a<*ain. Young animals are the subjects of this defect, and the causes are generally, as in. the instances of elongated round ligament, congenital. It is possible that the dislocation of the patella in a young animal may be followed by relaxation of the internal lateral ligaments ; but in this case the defect would only appear in one limb, whereas in the congenital disease in foals the relaxed condition equally affects both joints. It is very seldom necessary to use any means to adjust the dislocated bones, as they generally slip back into their places as soon as the foal assumes the standing position; and the constant attrition thus produced wears away the outer condyle of the thigh bone, with, which the patella articulates; and in consequence the retention of the floating bone in its position is rendered the more difficult the longer the disease continues. . When the animal is securely on his feet, and the patella has resumed its place, it can move with tolerable freedom, without displacing the bone ; but there is always a certain amount of rolling action in the hind extremities, which is suggestive of a relaxed condition of the round ligaments of the hip joint. Treatment is seldom attempted, because it is almost impossible to keep the patella fixed in its place for a sufficient length of time to allow the outer condyles of tho thigh bones to become developed and the inner ligaments to acquire strength to prevent the bono, to which they are attached from slipping. In an older animal frequent luxation of the patella would be met by repeated blisters, or perhaps by firing, the horso meanwhile being kept in a standing position to avoid the risk of the patella being shifted out of its place. Such means are quite inapplicable to an animal of a few weeks old, and therefore tho foal is left to take its chance in tho hope that it may improve in time ; the liope, however, is seldom realised. Relaxation of the lateral ligament of other joints may be the result of accident or of congenital weakness, but the cases winch have been described are those which are most frequently met with. In one instance only we had to deal with relaxation of the lateral.ligaments of the elbow joint, in a very small terrier. The animal moved very much in the manner of a dog with rickets, except that the giving way of the limb was confined to one side. The elbow joint was so loosely held together' that the bones could be separated from each other without difficulty, and during the experiment the animal gave no signs of suffering any pain. For some time various appliances were used to keep tho joint at rest, such as starch bandages, adhesive plasters, and a covering of adhesive mixture mixed with hair after the manner of a " charge;" but no benefit resulted from any treatment that was adopted, and at length the limb

became unable to support the animal's weight. The dog was destroyed, and on a post mortem examination being made the ligaments o£ the elbow joint, on the right side, were found to be so attenuated as to resemble a fine membrane. Nothing was known of the origin of this condition, but it is most probable that the elbow had been by accident dislocated, and, the injury not having been noticed at the time or properly treated, the constant motion of the separated bones had stretched the ligaments until they had lost all power of resistance, and were incapable of holding the bones in position when the dislocation was reduced.—From the Field.