—A chronic serous effusion into a joint is given the term hydrarthrosis. This condition is never primary; it is always the residue of some previous acute lesion, or else it is the result of neuropathic or rheumatoid changes going on in and about the joint, accompanied by relaxation of membranes permitting passive distention with fluid. The contained fluid is ordinarily pure serum. It may contain a little blood or numerous particles or shreds of fibrin, while in rare instances there will be found in it drops of oil or even fat crystals. The degree of distention of a joint capsule is the measure of the gravity of the case, as this membrane, like any other, will yield to gradual distention, although it at the same time undergoes thickening as a protective measure. Thus the synovia may, under certain circumstances, become as thick as the pleura. The result is a tough, leathery condition of this membrane, which makes it exceedingly difficult to manage. The joint thus involved will appear more prominent than it should, because of the atrophy of the surrounding structures. Accurate comparisons can only be made by measuring corresponding joints. Neighboring bursæ and tendon sheaths often participate in the distention. These collections are ordinarily painless, or nearly so, but interfere, to varying extent, with the function of the joint. Anatomical outlines disappear or are concealed by the bag of fluid. It is rare that there are any constitutional symptoms except perhaps those of the disease which causes the disturbance. The amount of fluid which may be contained in a long-distended knee-joint, for instance, is relatively very large. The prognosis in these cases will depend much upon the underlying cause, as well as upon the age, vitality, and docility of the patient.
Treatment.
—Removal of the fluid is always the indication. After reasonable effort has shown that this is not possible by the employment of massage, the actual cautery and elastic compression, combined with functional rest, it should be withdrawn by the aspirating needle or trocar. The more experience, however, we have with affections of this class the more we will realize that the interior of the synovial membrane is frequently studded with deposits, fringes, etc., which are not affected by mere aspiration, and the more cogent argument will be gained for sufficiently free incision to permit inspection of the interior of the joint, removal of tags of tissue, thorough washing out and sponging, by which a change in circulation and nutrition is certainly affected; and this may be combined with excision of a liberal portion of the thickened membrane, by which the dimensions of the joint may be materially reduced when the opening is sutured. For long-standing cases of well-marked hydrarthrosis, especially in the knee, the writer would urge this method of treatment. Drainage, if called for at all, can be made with strands of silkworm, or some temporary material which will quickly disappear or be promptly removed. This is particularly applicable for the milder forms of tuberculous synovitis, in which the joint is thus treated on the same principle that is applied in washing out a tuberculous peritoneal cavity.
Fig. 194
Arthritis deformans, knee. (Ransohoff.)
ARTHRITIS DEFORMANS AND OSTEO-ARTHRITIS.
Under this general name have been grouped a number of conditions, including the so-called rheumatoid arthritis, and referring to a variety of chronic progressive lesions of joints which involve the articular cartilages and synovial membranes, later the bones, and which produce more or less loss of function and deformity. Although often spoken of as “rheumatoid,” the condition has nothing to do with rheumatism as such, whatever that may be. It moreover presents no analogies to the forms of acute synovitis already described. These lesions are more common in women than in men, occurring oftener in those who have been sterile, and during or after the menopause. So far as their etiology and pathology are concerned, it is true, though it seem trite to say it, that they are the result of disturbed nutrition, which itself may be referred back to perverted trophic influences. Exposure, bad hygienic surroundings, improper food, mental perturbation, and depression are more or less potent factors in most of the cases. In some instances occurring in advanced age they seem to be due to changes ordinarily regarded as senile. When joint lesions are multiple and symmetrical, and accompanied by other nutritive changes, we may refer the cause back to the central nervous system. When monarticular they are more likely to be the residue of some previous infection or injury, such as gonorrhea, influenza, or an acute exanthem. If in connection with the joint manifestations we find the spleen and lymphatics enlarged, then the case may be regarded as doubtless infectious in nature.
The pathological changes within these joints include almost every imaginable alteration. Bones soften and atrophy at one point, or at another become enlarged and thickened, and throw out osteophytic projections by which the whole shape of the joint is materially changed. Cartilages atrophy here and thicken there, and disappear, at times, to an extent by which bone is exposed, the exposed surfaces frequently becoming polished or eburnated. The position of the joint and its general contour may be materially altered by these changes, and marked deformity or notable enlargement result. Subluxations are not infrequent, while the ligamentous structures are sufficiently strong to perform their function, and the joint yields or “wabbles.” Meanwhile the synovial membrane undergoes corresponding changes, and becomes distended with fluid so that hydrarthrosis is a frequent accompaniment.
On the other hand, there is another type of analogous changes where the tendency is atrophic throughout and little if any extra fluid accumulates. Such a joint may become smaller rather than larger, especially if, as in some cases, some part of the bone practically disappears.