Manual of Surgery Volume Second: Extremities—Head—Neck. Sixth Edition.

by Alexis Thomson; Alexander Miles

Fig. 124.—Advanced Tuberculous Disease of Knee, with backward displacement of Tibia.

White swelling is to be differentiated from peri-synovial gummata, from myeloma and sarcoma of the lower end of the femur, and from bleeder's knee. In the first of these the swelling is nodular and less uniform, and there may be tertiary ulcers or depressed scars in the neighbourhood of the patella. In tumours the swelling is more marked on one side of the joint, it is uneven or nodular, it does not correspond to the shape of the synovial membrane, and may extend beyond the limits of the joint, and it involves the bone to a greater extent than is usual in disease of the joint. Skiagrams show expansion of the bone in central tumours, or abundant new bone in ossifying sarcoma. The diagnosis of bleeder's knee is to be made from the history.

(5) Primary Tuberculous Disease in the Bones of the Knee.—So long as the foci are confined to the interior of the bone, it is impossible to recognise their existence, unless they are of sufficient size to cause enlargement of the bone or to be discernible in a skiagram.

The formation of peri-articular abscess takes place in rather more than fifty per cent. of cases. When left to themselves, such abscesses tend to spread up the thigh, or down the back of the leg between the superficial and deep layers of calf muscles, and numerous sinuses may result from their rupture through the skin.

Attitudes of the Limb in Knee-Joint Disease.—The attitude most often assumed is that of flexion, with or without eversion of the leg and foot. The flexion is explained by its being the resting attitude of the joint, and that which affords most ease and comfort to the patient. Once the joint is flexed, the involuntary contraction of the flexor muscles maintains the attitude, and if the patient is able to use the limb in walking, the weight of the body is a powerful factor in increasing it. The eversion of the leg is probably associated with contraction of the biceps muscle. Backward displacement of the tibia is met with chiefly in neglected cases of chronic disease of the knee when the child has walked on the limb after it has become flexed.

In certain cases, genu valgum or abduction of the leg is present along with a slight degree of flexion. The valgus attitude is associated with slight lateral displacement of the patella, with prominence and apparent enlargement of the medial condyle, with depression of the pelvis on the diseased side and apparent lengthening of the limb.

Treatment of Tuberculous Disease of the Knee.—Conservative measures are always indicated in the first instance, and are persevered with so long as there is a prospect of obtaining a movable joint.

Conservative Treatment.—If the joint is sensitive and tends to be flexed, the patient is confined to bed, the limb is secured to a posterior splint, and extension with weight and pulley persevered with until these symptoms have disappeared; during this time, from three to six weeks, methods of inducing hyperæmia and other anti-tuberculous procedures are employed. If it is proposed to inject iodoform or other drug, the needle is inserted into the interval between the bones on the medial side of the ligamentum patellæ or into the upper pouch when this is distended with fluid.

If there is no pain or tendency to flexion, or when these have been overcome, the limb is put up in a Thomas' splint ([Fig. 125]) and the patient allowed to go about. The splint is worn for a period varying from six to twelve months; before being discarded it may be left off at night; it is ultimately replaced by a bandage.