Wounds in Joints.—An accidental wound of a joint, as from a bullet or a fragment of shell or the blade of a knife, or a spike, is very serious, because of the risk of septic germs entering the synovial cavity at the time of injury. If the joint becomes thus infected there is great swelling with redness of the skin, and escape of blood-stained or purulent synovia. Absorption takes place of bacterial products and great constitutional disturbance arises. Blood-poisoning may thus threaten life, and in many cases ampu tation above the joint is the only course possible. Owing to the great extent of its synovial membrane and the difficulty of drain age, wounds of the knee joint are particularly dangerous. If the joint be saved probably it will be stiff permanently.
Dislocation.—The ease with which the joint-end of a bone is dislocated varies with its form and structure, and with the posi tion in which it happens to be placed when the violence is applied. The relative frequency of fracture of the bone and dislocation of the joint depends on the strength of the bones above and below the joint relatively to the strength of the joint itself. The strength of the various joints in the body is dependent upon either ligament or muscle, or upon the shape of the bones. In the hip, for instance, all three sources of strength are present; there fore in spite of the great leverage of the long thigh-bone, the hip is rarely dislocated. The shoulder, in order to allow of extensive movement, has no osseous or ligamentous strength; it is, therefore, frequently dislocated. The wrist and ankle a:e rarely dislocated; as the result of violence at the wrist the radius gives way, at the ankle the fibula, these bones being relatively weaker than the respective joints. The wrist owes its strength to ligaments, the elbow and the ankle to the shape of the bones. The symptoms of a dislocation are distortion and limited movement, with absence of the grating sensation felt in fracture when the broken ends of the bone are rubbed together. The treatment consists in reduc
ing the dislocation, and the sooner this replacement is effected the better—the longer the delay the more difficult it becomes to put things right. After a variable period, depending on the nature of the joint and the age of the person, it may be impossible to replace the bones. The result will be a more or less useless joint. The administration of an anaesthetic, by relaxing the muscles, greatly assists the operation of reduction. The length of time that a joint has to be kept quiet after it has been restored to its normal shape depends on its form, but, as a rule, early movement is advisable. But when by the formation of the bones a joint is weak, as at the outer end of the collarbone, and at the elbow-end of the radius, prolonged rest for the joint is necessary or dislocation may recur.
Congenital Dislocation at the Hip.—Possibly as a result of faulty position of the subject during intrauterine life, the head of the thigh-bone leaves, or fails throughout to occupy, its normal situation on the haunch-bone. The defect, which is a very serious one, is probably not discovered until the child begins to walk, when its peculiar rolling gait attracts attention. The want of fixa tion at the joint permits of the surgeon thrusting up the thigh bone, or drawing it down in a painless, characteristic manner.
The first thing to be done is to find out by means of the X-rays whether a socket exists into which, under an anaesthetic, the surgeon may fortunately be enabled to lodge the end of the thigh bone. If this offers no prospect of success, there are three courses open : first, to try under an anaesthetic to manipulate the limb until the head of the thigh-bone rests as nearly as possible in its normal position, and then to endeavour to fix it there by splints, weights and bandaging until a new joint is formed ; second, to cut down upon the site of the joint, to scoop out a new socket in the haunch-bone, and thrust the end of the thigh-bone into it, keep ing it fixed there as just described; and third, to allow the child to run about as it pleases, merely raising the sole of the foot of the short leg by a thick boot, so as to keep the lower part of the trunk fairly level, lest secondary curvature of the spine ensue. The first and second methods demand many months of careful treatment in bed. The ultimate result of the second is so often disappointing that the surgeon now rarely advises its adoption. But if, under an anaesthetic, as the result of skilful manipulation the head of the thigh-bone can be made to enter a more or less rudimentary socket, the case is worth all the time, care and atten tion bestowed upon it. Sometimes the results of prolonged treat ment are so good that the child eventually is able to walk with scarcely a limp. But a vigorous attempt at placing the head of the bone in its proper position should be made in every case.