rigidity. The diagnosis should be made by a consideration of the joint involved, of the age, of the nature of the force, by the length of the limb, by the fact that the patient could use the joint for at least a short time after the accident, and by the local feel and movements of the part. In some cases examine under ether, in some apply the X-rays. The prognosis depends on the size of the joint, on the extent of laceration, and on the amount of intra-articular hemorrhage. The danger is ankylosis.

Treatment. The first indication is to arrest hemorrhage. and limit inflammation. For the first few hours apply pressure and an ice-bag. Wrap the joint in absorbent cotton wet with iced water, apply a wet gauze bandage, and put on an ice-bag. In a mild sprain use lead-water and laudanum or apply at once a silicate dressing. In a severe sprain place the extremity upon a splint and to the joint apply flannel kept wet with lead-water and laudanum, iced water, tincture of arnica, alcohol and water, or a solution of chlorid of ammonium. The ice-bag should from time to time be laid upon the flannel for periods of twenty or thirty minutes. Leeches around the joint do good. Constitutionally, employ the remedies for inflammation (page 60). Morphin or Dover's powder is given for the pain. Judicious bandaging limits the swelling.

After a day or two, if the symptoms continue or if they grow worse, use hot fomentations, hot lead-water and laudanum, the hot-water bag, plunge the extremity frequently in very hot water, or apply heat by Leiter's tubes. When the acute symptoms begin to subside, rub stimulating liniments. upon the joint once or twice a day and employ firm compression by means of a bandage of flannel or rubber. Frictions should be made from the periphery toward the body. Many cases do well at this stage under the local use of ichthyol and lanolin (50 per cent.), tincture of iodin, or blue ointment. Later in the case use hot and cold douches, massage, frictions, passive motion, and the bandage. Van Arsdale treats these cases by massage almost from the start. Gibney treats sprains by strapping with adhesive plaster. Passive motion is begun a day or so after swelling ceases. If massage causes the swelling to return, abandon it for several days and then try it again. Blisters are used when tender spots persist and stiffness is manifest. If stiffness becomes marked, move the joint forcibly. Give iodid of potassium, use tonics internally, and insist on open-air exercise. If the person is gouty or rheumatic, use appropriate remedies.

Many sprains may be put up in an immovable dressing the first day or two after the accident. If the joint contains much blood, aspiration should be practised before the dressing is applied.

Ankylosis. When a joint-inflammation eventuates in the formation of new tissue in and about the joint contraction of this tissue limits or destroys joint-mobility, producing the condition known as "ankylosis." Ankylosis may be complete (bony) or incomplete (fibrous); it may arise from contractures in the joint (true or intra-articular ankylosis) or from contractures in the structures external to the joint (false or extra-articular ankylosis).

True or intra-articular ankylosis may arise from any cause which produces joint-inflammation with formation of new tissue, and may be due to wounds, contusions, sprains, dislocations, fractures in or near a joint, movable bodies in a joint, tubercle, gout, rheumatism, or syphilis. Want of use of the joints causes partial ankylosis, though this has been denied. Ankylosis is more apt to take place in a hingejoint than in a ball-and-socket joint. In ankylosis from a general cause (as rheumatic gout) many joints are apt to suffer. Ankylosis may be due to fibrous tissue, and is then usually partial; it may be due to chondrification of fibrous tissue, and is then incomplete; it may be due to ossification. of fibrous tissue, and is then complete, the joint being entirely immobile (osseous or bony ankylosis). The entire joint may be converted into bone. Only one small jointsurface may contain adhesions (limited adhesion), or the entire joint-surface may be bound up in them (diffused adhesion).

Fibrous ankylosis follows aseptic inflammations; bony ankylosis is apt to follow infections. Though slight motion is usually possible in fibrous ankylosis, in some cases it may be impossible. A joint immovable from fibrous ankylosis is distinguished from a joint immovable from bony ankylosis by the fact that in the former attempts at motion are productive of pain, and subsequently of inflammation. incapacity resulting from ankylosis is due, first, to the impairment or destruction of joint-function, and, secondly, to the fixation at an inconvenient angle (a fixed flexed knee is worse than a fixed extended knee; a fixed extended elbow is worse than a fixed partly flexed elbow).

The

Treatment.-The effort should always be made to prevent an ankylosis by treating carefully any joint-inflammation and by beginning passive motion at the earliest safe period. To limit inflammation is to prevent ankylosis. Many cases of

fibrous ankylosis are improved by passive movements, massage, frictions, stimulating liniments, inunctions of ichthyol or mercurial ointment, hot and cold douches, hot-air baths, and electricity. Some cases may be straightened out slowly by screw-splints or by weights and pulleys. Fibrous ankylosis of the elbow is best treated by using the joint. Fibrous ankylosis is often corrected by forcible straightening. If the tendons are much contracted, tenotomy should be performed two or three days before forcible. straightening is attempted. In order to straighten, always give ether. Suppose a case of ankylosis of the knee: put the patient upon his back, bring the leg over the end of the operating-table, grasp the ankle with one hand and the lower portion of the leg with the other hand, and make strong, steady movements of flexion and extension until the limb can be straightened. The adhesions will be felt to break, the snapping often being audible. At once apply a plaster-of-Paris dressing, and keep the limb immobile for two weeks. This procedure is not free from danger. Vessels may be ruptured, nerves may be torn, skin and fascia may be lacerated, suppuration may ensue from the admission into the joint of encapsuled cocci, or of organisms in the blood which find in this area a point of least resistance. Because of the danger of opening up depots of encapsuled bacilli and cocci, do not forcibly break up an ankylosis that results from a tubercular or a septic arthritis, but use gradual extension by weights or by screw-splints. Ankylosis of the knee following fracture of the patella is almost sure to recur after forcible breaking up. The best treatment for knee-ankylosis is use of the joint. In bony ankylosis of any joint other than the elbow-joint do nothing if the joint is in a useful position. If the joint is firmly fixed in an unfortunate position, resort to excision or an osteotomy. In the elbow excision should be performed, no matter what the position, in the hope of obtaining a movable joint. In ankylosis of the jaw surgeons are apt to try to remedy the condition by wedging the jaws apart with a mouth-gag, and afterward inserting boxwood plugs at frequent intervals. This method is invariably a failure. Esmarch's operation is sometimes curative (removal of a wedge-shaped piece of bone). Some operators excise the condyle and a portion of the neck. Swain advocates sawing the bone at the angle.

False or Extra-articular Ankylosis.-In this disease the joint is intact, but the contractures are in surrounding

1 Swain, in Lancet, 1894, vol. ii., p. 187.

parts. The causes are muscular, fascial, and tendinous contractures, cicatrices (especially from burns), deposits of bone, muscular paralysis, tumors, and aneurysm. Contractions of muscles or tendons may be due to gout, rheumatism, injury, thecitis, fractures, and dislocations. False ankylosis is seen in club-foot and in Dupuytren's contraction.

Treatment-The treatment of false ankylosis depends upon the cause. Recently contracted muscles or tendons require motions, massage, frictions with stimulating liniments, and hot and cold douches. Old contractions require division. Whenever possible, excise a cicatrix that causes false ankylosis, and fill the gap with good tissue. Bony deposits are gouged away and tumors are removed. Contractures in cases of paralysis require electricity, passive motion, frictions with stimulating liniments, the hot-air bath, and general treatment.

Loose Bodies in Joints (Floating Cartilages).-The knee is the joint oftenest affected. These bodies may be free, may have a stalk or pedicle, may move about and occasionally block the joint, or may lie quietly in a joint-recess or diverticulum. They may be single or multiple, flat or ovoid, smooth or irregular, as small as peas or as large as plums, and may be composed of fibrous tissue, of bone, or of cartilage. There are numerous different modes of origin of these bodies, many being "detached ecchondroses or pieces of hyaline cartilage hanging by narrow pedicles" (J. Bland Sutton), and they result from enlargement and chondrification of the villi of the synovial membrane. Some loose bodies are broken-off osteophytes; some arise from bloodclots; some by projection or herniation of the synovial membrane, which protrusion is broken off; others are detached fringes of tubercular synovial membrane. Traumatism is usually an exciting cause. Loose cartilages are commonest in adult men.

Symptoms. Many small bodies give rise to no symptoms other than those of synovitis. A large body produces pain and interferes with joint-function. The joint is weak and a little swollen, and the patient can feel the body and often can push it into a superficial area of the joint, where it may be felt by the surgeon. From time to time the body may get caught, thus suddenly locking the joint and producing intense and sickening pain, extension and flexion being impossible until the body slips out. This accident is followed by inflammation and effusion.

Treatment. To relieve locking, employ forced flexion and

sudden extension. Cure can be obtained only by operation. Asepticize with the utmost care. Let the patient bring the foreign body to a point where it can be felt; the surgeon then fixes it with a pin or holds it with the fingers, ether being given or cocain being used. The joint is now opened, the foreign body extracted, and an exploration made to see that no other bodies are present. The wound is now stitched and the leg is placed upon a splint. Asepsis must be most rigid. The operation does not cure the causative lesion, and these bodies are apt to form again.

4. LUXATIONS OR DISLOCATIONS.

A dislocation is the persistent separation from each other, partially or completely, of two articular surfaces. A selfreduced dislocation is called a sprain. There are three forms of dislocation: (1) traumatic; (2) spontaneous or pathological; (3) congenital.

1. Traumatic dislocations are due to injury. They are divided into-complete dislocation, in which the two articular surfaces are entirely separated and the ligaments are torn; incomplete or partial dislocation, in which the two articular surfaces are not completely separated and the ligaments are rarely lacerated; simple dislocation, in which the articular surfaces are not brought into contact with the external air; compound dislocation, in which the external air has access to the articular surfaces; complicated dislocation, in which, besides the dislocation, there is a fracture, extensive damage of the soft parts, an opening admitting air to the soft parts, or damage of a nerve or blood-vessel; primitive dislocation, in which the bones remain as originally displaced; secondary dislocation, in which the bone assumes a new position: for instance, a subglenoid luxation of the humerus is primary, and it may become secondarily a subcoracoid luxation because of muscular contraction or attempts at reduction; recent dislocation, in which the displaced bone is not firmly fastened by tissue-changes in its new situation, and its old socket is not obliterated; old dislocation, in which the displaced bone is firmly fastened by tissue-changes in its new habitat, and the old socket is to a great extent obliterted (whether a dislocation is old or new depends on the state of the parts rather than on the time which has elapsed since the accident); double dislocation, in which corresponding bones on each side are dislocated; single dislocation, in which only one joint is dislocated; unilateral dislocation, in