permitting movement in the joint may be used after about six weeks, but it must be kept on for a very long time.

The results of complete arthrectomy in pure synovial disease are extremely satisfactory. The disease is cut short and the patient is quickly restored to health; the only trouble is the tendency to flexion referred to above. In adults, however, when a firm limb is desired excision is much more satisfactory than arthrectomy, because strong bony anchylosis is obtained. And in adults the question of the epiphyseal line which negatives excision in children does not arise.

Excision. During the operation it is well to avoid the use of a tourniquet for the reasons mentioned under arthrectomy. The best incision is one with its convexity downwards, commencing over the centre of the lateral aspect of the joint, running down to the lower part of the tubercle of the tibia, and then curving upwards to a corresponding point on the opposite side (see Fig. 82). The flap thus marked out is turned up, so as to expose the whole of the capsule of the joint.

FIG. 82.-INCISION FOR EXCISION OF THE KNEE. The lowest point of the incision should reach the lower part of the tubercle of the tibia.

The first question that arises is whether the patella should be removed or not. In most cases it is well to take it away, and the only real objection to this is that the divided extensor may contract adhesions to the lower end of the femur rather than to the tibia, and there will not then be such good leverage as if the patella were left. This can easily be prevented by peeling off the periosteum from the anterior surface of the patella, and thus shelling the bone out of the quadriceps tendon instead of dividing the latter transversely above the bone. The best way to do this is to have the skin flap held well out of the way, and to make a vertical median incision through the quadriceps from the top of the supra-patellar pouch down to the tubercle of the tibia. This incision is very carefully deepened above the patella until the muscular fibres are cut through, when the handle of the knife can be sunk between the muscle, and the capsule and the two structures separated from one another. The periosteum over the patella is then turned off to either side with a raspatory, and the ligamentum patellæ is split longitudinally.

The muscle is now raised from the capsule of the joint on each side until the whole of the supra-patellar pouch and its lateral prolongations have been exposed. The steps of this procedure are identical with that for arthrectomy (see p. 204). The margin of the quadriceps tendon is defined below, and then the supra-patellar pouch and the whole of the anterior portion of the synovial membrane are removed, including

the patella and the fatty pads below it. The knee is fully flexed, the lateral ligaments are divided, and the synovial membrane over each side of the joint is taken away. If it should be necessary in order to obtain freer access to the joint, the tendon of the quadriceps may now be divided transversely, the two ends being stitched together at the end of the operation. After the crucial ligaments have been divided and the knee fully flexed, the end of the femur is protruded and its articular surface removed. In doing this the limb is held horizontal, and the bone sawn vertically at the upper limit of the articular cartilage on the front of the femur. The line of bone section should be at right angles to the long axis of the limb and not to that of the femur. As the posterior surface of the femur is reached, care must be taken to see that the structures in the popliteal space are kept out of the way and protected by a spatula if necessary.

When the end of the femur has been removed, the posterior part of the capsule is easily separated and removed, in the manner already described for arthrectomy (see p. 205), and the head. of the tibia is then protruded through the wound and its articular surface sawn off. In doing this the knee must be flexed, the foot being placed flat upon the table so that the leg is vertical; the saw is applied at right angles to the long axis of the tibia, and about half an inch of the upper end is removed.

FIG. 83.-RELATION OF THE EPIPHYSEAL CARTILAGE TO THE BONE SECTION IN EXCISION OF THE KNEE. The lower figure is a lateral view, showing the epiphyseal cartilage as a white line and the saw-cut as a dark one. The upper figure is a front view of the same femur, and illustrates the relation of the bone section to the edge of the articular cartilage in front. It will be seen how easy it is to encroach unduly upon the line of growth when sawing the bone. (Holmes's System of Surgery.)

The wound is now examined to see that none of the capsule nor any osseous deposits are left behind. Any portions of articular cartilage which have been left are carefully clipped away; any projecting edges of the bones are removed with bone pliers, and any tuberculous deposits present in the cut surfaces of the bones are scooped out, together with a portion of the healthy bone around.

The bleeding is arrested and the wound stitched up, but before doing this it is well to fix the femur to the tibia by wires or plates; this is

not essential, but it keeps the limb in position and prevents any anteroposterior dislocation of the bony surfaces. It must be remembered that the divided surface of the tibia is much broader than that of the femur, and if the anterior margins of the two bones are brought into apposition, the posterior surface of the tibia will project markedly into the popliteal space, and, when the limb is placed upon the splint, serious pressure may be exerted upon the popliteal artery, and gangrene of the limb may result. The posterior margins of the bones should therefore be accurately adapted, and it is with the view of insuring this that fixation of the bones is advisable. Some trouble may be caused by the extreme softness of the bone, which allows the wires or plates to become loose, and therefore great care must be taken to fix the limb firmly with splints.

As a rule, it is well to introduce a drainage tube at the outer edge of the incision, the rest of which is sewn up by a continuous suture; the limb is placed upon a Gooch's splint prepared in the way recommended for arthrectomy (see p. 206).

After-treatment.-When a drainage tube has been used, the dressing must be changed next day, and about the third day the tube may be removed. Before changing the dressing, it is well to have a fresh splint prepared in a similar manner to the original one. The splint is then opened and the front of the knee dressed; while this is being done, an assistant must fix the thigh to prevent starting of the limb, while another similarly fixes the leg. It is well at the first dressing to keep the limb in contact with the splint by opening and dressing one side at a time whilst the limb is pressed against the other. The splint is then elevated, the inclined plane or pillow upon which it is resting removed, and one assistant grasps the thigh and another the leg, whilst the surgeon grasps the limb on either side of the knee; the splint is then allowed to drop away from the limb, the posterior part of which is thoroughly washed with 1 in 20 carbolic acid solution, and afterwards with 1 in 2000 sublimate. The fresh splint, with the dressing already arranged, is put in place beneath the limb and gradually raised until the surgeon and the assistants can remove their hands and leave the limb lying upon it. The strips of gauze and wool are then wrapped around the knee and the fresh splint fixed on by bandages. At the end of three weeks this splint may be left off, and the limb put up in plaster of Paris or some similar immovable apparatus.

In three months after the operation, union is usually firm enough for the patient to get about. Massage will then be required to restore the circulation and improve the nutrition of the muscles. The tendency to flexion must be borne in mind, and therefore a moulded leather splint or some similar apparatus should be worn during the day for some months or even years.

When septic sinuses are present. The presence of sepsis is a very

serious complication, and the chances of recovery are by no means good. In children these sinuses will sometimes heal if the limb is thoroughly immobilised and the patient placed under good hygienic conditions. At the same time healing is rare, and the patient is very apt to go downhill, especially if there be much pain. Apart from fixation. and good hygienic conditions, the main point is to try to get the sinuses. aseptic and provide free drainage. The treatment of these sinuses has been fully discussed in Vol. II. p. 457. If these methods fail, operation must be resorted to.

The operations are arthrectomy or (very occasionally) amputation in children, and excision or amputation in adults. The crucial point in these cases is the presence of sepsis, and special efforts must be made to eradicate it, especially if arthrectomy or excision is to be done. At the commencement of the operation the sinuses should be carefully scraped, after the skin has been thoroughly purified, and a piece of sponge soaked in undiluted carbolic acid should be introduced into each sinus and left there. The orifice of each sinus should then be included in an elliptical incision and its track dissected out. Should the sinuses lie in the line of the ordinary incision they will, of course, be removed during the deepening of the wound. After the synovial membrane has been taken away, it is well to sponge the entire wound with undiluted carbolic acid, which is allowed to act for about five minutes and is then washed away with 1 in 2000 sublimate solution. No symptoms of carbolic acid poisoning need be feared. Drainage tubes must be used.

When the general condition is bad, amputation through the lower third of the thigh is the best treatment, especially in adults; the patient recovers at once, there is much less shock, and little fear of recurrence.

Treatment of the fourth stage. When recovery is taking place with anchylosis of the joint in a faulty position, the treatment consists essentially in rectifying the deformity. If the union is fibrous and comparatively slight, continued extension may be tried with the view of bringing the limb straight, but this is rarely successful, because the adhesions in the joint are generally accompanied by marked shrinking of the ligaments and shortening of the muscles in the neighbourhood. If extension is to be employed, it is well to divide these structures in the first instance, and the weight should be gradually increased. In the great majority of cases, however, some more extensive operation will be necessary.

In a child. In children, when there is only fibrous anchylosis and the disease is still active, arthrectomy should be performed if extension fails to bring the limb into proper position. This allows free access to the various ligaments about the joint, which can be divided and the limb brought into proper position. When no active disease is present, and the union is too firm for extension to have any

effect, the best treatment is to allow the child to get about and to have the limb well massaged; when growth is nearly complete-at from sixteen to eighteen years of age-the case can be treated as described below. To interfere by operation in the case of children is to incur the risk of destroying the epiphyseal line, with consequent imperfect growth of the limb.

In adults the usual plan is to remove a wedge from the bone, so planned as to bring the limb into proper position and then to fix the bones together by plates or wires, so as to obtain bony union. We have

FIG. 84.-CUNEIFORM EXCISION OF THE KNEE FOR ANCHYLOSIS WITH DEFORMITY. The thick lines show where the bone will require to be divided in order to get the limb straight. From this it is obvious that the region of the epiphyseal line must necessarily be encroached upon.

already referred to Murphy's arthroplasty (see p. 153), which offers a promising alternative to the older plan.

RHEUMATOID ARTHRITIS.

This affection is common in the knee. The characteristic deformities are flexion and outward rotation of the leg, and there is sometimes a certain amount of genu valgum. The symptoms have already been described (see p. 142).

TREATMENT.-There is very little to add to what has already been said in discussing the treatment of the disease in general (see p. 143). Special care should be taken to remove any septic focus, such as pyorrhoea alveolaris.

Operative interference, such as gouging or drilling the condyles of the femur for excessive pain, or removal of osteophytes in the rare instances in which they interfere mechanically with the movements of the limb, may be called for. Excision is also of value in cases in which there is great pain and disability.

In speaking of the treatment of osteo-arthritis in general, we referred to the question of excision of joints in the monarticular form of the disease.