—Rice-grain bodies may be suspected in cases of chronic tuberculosis and often in arthritis deformans, while in many instances they may be felt gliding beneath or between the joint structures. A perfectly loose floating body will produce symptoms which are quite distinctive. They consist of sudden and intense pain, with such muscle spasm as to fix the joint and prevent its use, thus “locking it.” Occurring at the knee the individual is instantly disabled, but usually learns by some peculiar manipulation, with or without assistance, to “unlock” the joint, and after a few moments to resume its use. Such a complaint as this should always suggest the condition. Patients who have had it for a long time learn how to avoid it as well as how to relieve it, and will often discover and be able to indicate to the surgeon the existence of a movable body, and even to describe its usual resting place.

Partial or complete dislocation of a semilunar cartilage in the knee is usually the result of traumatism, a distinct history of which can generally be obtained. It may not have been discovered at the time, owing to swelling or tenderness, but will produce its peculiar symptoms later, i. e., after use of the joint is resumed. Here, again, so long as it remain in proper position, it interferes but little; with a misstep or sudden movement, however, the patient is seized with sudden and painful disability. Here the movable cartilage may be felt projecting near its proper location. In such cases as these it is movable only to a certain extent and makes no free excursion about the joint. When not detected it may be suspected from the description which the patient gives of his seizures.

Diagnosis.

—So far as diagnosis is concerned, when a movable body can be felt all doubt is set at rest. When it cannot be discovered its existence may be inferred with an accuracy proportionate to the patient’s description of his difficulties.

Treatment.

—The treatment of rice-grain bodies is essentially that of the chronic hydrarthrosis and probably tuberculous condition which have led to their formation. It will consist usually in arthrotomy, with thorough irrigation; often in some form of arthrectomy. With the larger floating bodies, the “joint mice,” the most radical measures are the best. In most of these instances there will be some degree at least of hydrarthrosis. The joint cavity being distended and relaxed, the indication for arthrotomy is the more urgent, since it will permit also of irrigation or of dry sponging, with the same benefit with which analogous intraperitoneal conditions are treated by the same measures. The joint may be opened by a sufficiently ample incision, through which the foreign body or bodies may be removed. The operator should not be satisfied with mere removal of one, but should make a thorough search for others which may have escaped previous detection.

Perhaps no operative measure in surgery better illustrates the advantages of asepsis. This operation, which now can be done with impunity, was in the pre-antiseptic era one which had a discouraging fatality, death resulting from septic infection in about 40 per cent. of cases.

FOREIGN BODIES IN THE KNEE-JOINT.

“Joint mice” are of sufficient frequency and significance to justify brief separate consideration. According to Connell these may be grouped as follows: