PART II. PRACTICE OF SURGERY
SECTION III. DISEASES
Part 13. 3. Diseases of Joints
A joint is a complicated organ, and its integrity depends upon a healthy condition of the bones which form it, of the articular carti-lages which cover the ends of the bones, and of the synovial mem-brane which supplies the synovial fluid that lubricates the joint. These different structures are closely associated anatomically and physiologically, and disease beginning in any one of them will assuredly, unless checked, gradually extend to the others. The cartilage covering the ends of the bones receives its blood-supply mainly from the bone, and is also to a certain extent supplied at its edges by the synovial membrane. The cartilage being in itself non-vascular, disease does not commence in it; the majority of joint diseases commence either in the synovial membrane or in the bone ; as a general rule they begin with some slight injury of the joint. These injuries consist of strains or twists (of the joint) on the one hand and jarring or contusion on the other. In the latter case the elastic cartilage lessens the force of the contusion.
When a joint is strained, the ligaments binding the bones to-gether are stretched and the synovial membrane becomes inflamed. Sprain. Consequently effusion takes place into the joint, which becomes swollen and painful on pressure. Any movement of it is painful, and all the muscles around it are rigid. In a healthy person appro-priate treatmentrest, hot fomentations, and gentle elastic pressurewill cause the fluid within the joint to be gradually absorbed, after which the joint can be restored to its normal condition. When the inflammation becomes sub-acute the pain disappears, and unless the joint is kept quiet by appropriate splints the condition is very apt to become chronic ; that is, the joint becomes swollen and the omovements are restricted. This condition is most persistent, and prolonged rest, along with counter-irritation by blistering or by the application of tincture of iodine, is necessary before the effusion subsides. The joint may remain weak for the rest of the patient's life. Fibrous adhesions may form and prevent free move-ment. A joint in such a condition is always liable on the slightest injury to have a return of the effusion in an acute or sub-acute form. These are the chief consequences of a strain in a healthy person. In a weakly person the primary strain may entail a very different result. The synovial membrane may undergo gelatinous oi- pulpy degeneration, and, although it is improbable that this condition is associated with the tubercular diathesis in all cases, there can be no doubt that in very many the degeneration of the synovial membrane is tubercular in character. The tubercle bacil-lus has been found in the thickened membrane. A joint in this condition swells; the enlargement, although it may be due in part to effusion into the cavity of the joint, is mainly caused by the thicken-ing of the synovial membrane, which has a peculiar doughy semi-elastic feeling. The movements of the joint are restricted, though little pain is complained of. If it is an upper limb the patient will not use it, if a lower limb he will walk with a distinct limp. The disease is a chronic one, and the joint may remain in this con-dition for months. Rest, elastic pressure, and blistering may check the progress of the disease, but as a rule, sooner or later, and very often as the result of some slight injury, a change takes place. On the one hand, the effusion within the joint, instead of being serous, becomes sero-purulent and even purulent, owing to the formation of pus within it. If the joint is an important one, inflammatory fever is set up ; the joint becomes intensely painful on the slightest movement, and unless incisions are made to allow the pus to escape it passes gradually into a state of complete dis-organization. The cartilage softens and breaks down, so that gradually the cancellated bone underneath is exposed. A similar change takes place in the opposing cartilage. It is destroyed in its turn and the ligaments binding the bones together are softened and lose their elasticity, so that the joint can be moved in abnormal directions. A grating sensation can be felt when the cancellated bony surfaces are rubbed together. Along with these changes within the joint, foci of inflammation form in the soft tissues around it. These inflammatory areas suppurate ; the abscesses burst into the joint; the skin over them gives way; and com-munication is established between the external air and the cavity of the joint. Through this channel the causes of putrefaction reach the cavity, and complete disorganization of the part accom-panied by sepsis occurs. Should the joint be an important one, a condition termed hectic is set up. If the discharge is allowed to continue, a gradual wasting takes place, which sooner or later ends in the death of the individual, unless the surgeon either re-lieves the tension by free incisions, or excises the joint, or amputates the limb. After disorganization has occurred, if the inflammatory process ceases, anchylosis of the joint may result. But, if the joint is freely drained and kept at rest, the inflammation will subside, and the granulation tissue on the two opposing surfaces will unite and a fibrous formation take place. The process may stop there, or the fibrous tissue may be gradually transformed into bone. Osseous union has taken place between the hones forming the joint. In many cases this is what the surgeon aims at, and it is of great importance to keep it constantly in view and to place the joint in such a position that, if anchylosis does occur, the limb may be as useful as possible. This result is only attained after prolonged treatment, and, if the patient's strength is unequal to it, it will be necessary to excise the affected joint or to amputate the limb. Suppuration sometimes occurs within a joint without any previous pulpy degeneration of the synovial membrane, either as the result of a wound or from septic inflammation secondary to pyaemia, or in consequence of a very acute simple synovitis resulting from excessive tension within the joint. When the synovial membrane is affected with pulpy degeneration the vitality of the cartilage at its edges, wdiere it joins the synovial membrane, may be interfered with: the thickened synovial membrane, by encroaching on the articular cartilage, gradually by pressure alters the nutrition of the cartilage so that it disintegrates and breaks down, and when it is destroyed disorganization of the joint ensues, as already described. Should the disease assume this form, if care is taken, and if the joint is kept quiet, suppuration within it need not necessarily take place. The inflammation may assume a sub-acute type and fibrous anchy-losis occur.
"When a joint has been severely contused, separation of the cartilage
tusion. from the bone occurs ; effusion then takes place between the carti-lage and the bone; the cartilage is cut off from its nutrient supply; and, unless the joint is kept at complete rest, unless the effusion is absorbed, the cartilage will sooner or later become necrosed. The necrosed cartilage will give way ; the bone beneath will be exposed ; and, if the irritation is kept up, effusion, at first serous but soon becoming purulent in consequence of the tension within the joint, will take place. Changes follow in the opposing carti-lage, which has been itself bruised by the primary jar, and perhaps even separated from the bone beneath. It will in its turn necrose, and the bone will be exposed, suppuration taking place within the joint. The synovial membrane will become diseased, the liga-ments softened, and the evil sequence of events already described will ensue. A joint affected in this way is easily recognized from one in which the synovial membrane is primarily affected by the absence of swelling and by the intense pain. In the early stages complete rest should be obtained by affixing a weight to the affected limb. This, by setting up between the opposed and in-jured cartilaginous surfaces a condition of negative pressure, will tend to check the disease. But if this plan of treatment does not soon cause a subsidence of the pain, actual cautery must at once be resorted to. Contusion in wdiich the cancellated bone is injured at some distance from the cartilage is most commonly met with in young people, in whom the extremities of the bones are not fully developed. In them the epiphyseal cartilages are richly supplied with blood for the performance of their physiological function, the formation of bone, and a comparatively slight in-jury may cause inflammation to be set up in the bone immediately in contact with the epiphyseal cartilage. As in the synovial mem-brane when it is affected with pulpy degeneration, this disease may be occasionally non-tubercular in character ; but in the majority of cases, more especially when the primary injury is very slight, the disease assumes the tubercular type and tubercle is deposited. In such cases the symptoms are often very insidious ; the young patient complains of some slight uneasiness, or the first thing to be noticed is a limp in walking when a lower limb is affected. In the case of an upper limb the patient will avoid moving the affected joint. As there is no external swelling, the disease may be overlooked in its early stages ; but, if it is suspected, and if the affected limb is kept at rest, the inflammation will subside and recovery ensue. On the other hand, if the patient is allowed to use the limb, even in an imperfect way, the tubercular area may extend and the articular cartilage become affected. The articular cartilage does not in that case receive its proper nourishment: it disintegrates, breaks down, and the disease attacks the joint. Into this last tubercular matter escapes and suppuration occurs, result-ing sooner or later in disorganization of the joint.
In recent years a useful limb has often been saved by excision of the affected joint. In the early stages the disease may subside under appropriate local treatment, such as counter-irritation, rest, pressure, assisted by constitutional treatment, such as tonics, fresh air, and careful dieting. By these means an operation may be avoided, and in applying such treatment it must be remembered that, wdiile the disease itself may subside, the joint as an organ may Anchy- be irretrievably damaged: it may become anchylosed. If anchylosis losis. occurs in a flexed position of the hip or knee joints, the limb will be useless for progression ; and an operation will be necessary in order to straighten it. In the ankle joint, if anchylosis occurs with the foot in an extended position, the patient will not be able to put his heel to the ground, and an operation will be necessary to bring the foot at right angles to the leg. Do not interfere with an anchylosed joint in the lower limb if it is in good position. If the shoulder joint becomes anchylosed after disease, the sterno-clavicular and acromio-clavicular joints take up to a great extent the function of the anchylosed shoulder. In the elbow, in what-ever position the joint becomes anchylosed, the arm loses much of its usefulness and excision of the joint is performed in order to get a movable elbow. In the wrist it may be necessary to operate for anchylosis ; but as a rule, if the fingers are mobile, the anchylosed wrist does not interfere to any great extent with the usefulness of the hand.
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