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CHAPTER IV

RICKETS

RICKETS is a so-called ' deficiency ' disease, due to faulty feeding and lack of sunlight. It is a disease of the whole body, but the chief manifestations are in the bones. It is most common among children artifici-ally fed and in the first three years of life, though it may occur later during the growing period. Essen-tially, it is caused by lack of vitamin D, a chemical substance present in maternal and un-boiled cow's milk, cream, butter, and other foods. This vitamin is formed also by the action of sunlight on the natural fats secreted in the skin glands. In the body, it is concerned with the deposit of lime salts in growing bone, by which the bones are hardened. Hence, when the supply of the vitamin is deficient, the bones are softened and the epiphysial cartilages are enlarged, because new cartilage is formed by growth, but remains uncalcified.

A child afflicted with rickets usually looks fat and well, though he is apt to suffer from digestive and respiratory disturbances. The teeth are soft and decay rapidly and the muscles lack normal tone. The head is quadrangular in shape and the fontanelles are large and close late. The chest is flattened from side to side, making the sternum prominent (' pigeon-breast '). On each side of the lower part of the chest is a horizontal groove, known as * Harrison's sulcus. The junctions of the ribs and costal cartilages are enlarged, forming a line of nodes on each side, the so-called ' rickety rosary \ The enlargements of the

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epiphysial cartilages at the wrist can be seen or felt. The abdomen is prominent.

The deformities in rickets are produced by gravity and weight-bearing, acting on the softened bones and atonic muscles. They tend to vary according to whether the disease is most active when the child is at the stage of sitting, crawling, or walking. The spine may be uniformly backwardly curved, or may develop

Fig. 32.—Bow-leg due to rickets. Fig. 33.—Genu varum due to rickets.

a lateral curvature if the child is carried habitually by the mother on one arm. The arms and forearms may become curved during crawling. The most common deformities are seen in the lower limbs. There may be outward or forward bowing of the tibia and fibula (bow-leg) (Fig. 32) ; outward bowing of the whole length of the limb, most marked at the knee (genu varum) (Fig. 33) ; forward and outward bowing of the femur ; decrease of the normal angle of the neck and shaft of the femur (coxa vara) ; increase of the

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normal inward angulation of the limb at the knee (genu valgum or knock-knee).

Activity of the disease is determined with certainty by X-ray examination, which shows characteristic appearances at the junctions of the epiphyses with the shafts of the long bones. When, sooner or later, the body comes to be supplied with a sufficiency of vitamin D, the bones become hardened ; but the deformities are thereby fixed and persist, though the disease is no longer active.

TREATMENT

Rickets is entirely preventable by correct dieting and hygiene. If the infant cannot be naturally fed, artificial food should be supplemented with cod- or halibut-liver oil, which is rich in vitamin D. Frequent exposure of the whole body to air and sunlight should also be made. This is also the treatment of the disease when established. Deformities should be prevented by keeping the child recumbent while the disease is active. He can be prevented from sitting up by means of a cloth chest-band fixed to the sides of the cot with webbing straps. Large napkins should not be used because they may cause outward bowing of the thighs. The child should not be allowed to cross one leg over the other, as the mere weight of one limb on the other is enough to produce deformity.

If deformity is present and the disease active, daily manipulation may mould the soft bone back into normal shape. But this is apt to be painful and is often not possible without an anaesthetic. The surgeon may decide to do this, or to make gradual correction by means of a splint, according to the particular deformity present and the age of the patient.

Bow-leg, if slight, is treated by a padded wooden splint, applied on the inner side of the leg from above

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the knee to the foot, towards which the bowed leg is drawn by bandaging or by broad webbing straps. When the child is allowed to walk, the lower end of the splint is fitted into a pocket in the upper of the shoe. In more severe cases, the surgeon forcibly bends the bone straight over an orthopaedic wedge ; or, if the disease has ceased and the bones are hardened, he fractures the bones partially at the point of maximum curvature manually over a wedge (osteoclasis), or divides the bones by open operation (osteotomy). After any of these procedures, the leg is fixed with the deformity corrected, either in wooden splints or in plaster-of-Paris. Subsequently, when the bones have re-united, the child walks with the wooden splint applied as described above.

Genu Varum requires a splint reaching to the top of the thigh. In severe cases the deformity may be corrected by division of the femur above the condyles (supracondylar osteotomy),

Genu Valgum is more often a postural disorder than due to rickets. The symptoms, signs, and treat-ment of the deformity are described on p . 34.

Coxa Vara is a much less common deformity in rickets than either bow-leg or knock-knee, and is usually not evident until an older age. In this deformity, the angle between the neck and shaft of the femur is diminished. It may be due to causes other than rickets, such as injury or disease of the head or neck of the femur. In rickety deformity, the symptoms are not marked, except in bilateral cases, when lordosis and waddling gait are present. The greater trochanter is at an abnormally high level, above Nekton's line. Abduction and internal rotation of the hip are limited.

In a young child, the deformity may be corrected by gradually abducting the limbs while the child is

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kept on a double abduction frame. In older children, it is necessary to divide the femur just below the greater trochanter (subtrochanteric osteotomy), after which the limb is forcibly abducted and fixed in plaster-of-Paris until the bone has reunited in the corrected position.

Deformities of the Spine during the active stage are prevented by recumbency. When present, they may be gradually corrected by fixation in a plaster-of-Paris bed. Later, exercises are used, and in a few cases a spinal supporting appliance is necessary.

Deformities of the Upper Limbs rarely call for treatment, since they usually cause no disability.

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