Fig. 154.—Imprint of Normal and of Flat Foot.
Skiagrams are useful for showing displacement of bones and differences between sitting and standing, and for recording the results of treatment.
Prophylaxis of Flat-foot.—Stress is to be laid on a supervised training of the whole muscular system, and especially of that of the legs. In walking and standing, the feet should be kept parallel and not pointed outwards, as was formally taught in schools of gymnastics and insisted upon by drill instructors. Children should be taught to walk properly, rising on the balls of the toes with each foot in succession. Attention should also be directed to the boots, which should be so fashioned that the medial side of the boot is kept straight and the end of the boot is opposite the big toe.
Treatment.—This is directed towards restoring and maintaining the arch of the foot. As the measures adopted necessarily vary with the extent to which the condition has progressed, it is convenient for purposes of treatment to recognise the following four degrees. A first degree, in which the arch reappears when the weight is taken off the foot or the patient rises on the balls of the toes; a second, in which the normal attitude can be restored by manipulation; a third, in which this is only possible under anæsthesia; a fourth, in which the bones are so displaced and altered in shape that correction is impossible without operation.
Cases of the First Degree.—If there is marked pain and tenderness, the patient must lie up. The general health is improved by a nourishing diet and by cod-liver oil and tonics; and the legs and feet are douched and massaged thrice daily. When pain and tenderness have disappeared, the patient is instructed how to walk and exercise the feet. In walking, the medial edges of the feet should be parallel with one another, first the heel should touch the ground and then the balls of the toes. He should neither stand nor walk long enough to cause fatigue, and in standing he should alter the attitude of the feet from time to time, and occasionally rise on the balls of the toes. The following exercises, devised by Ellis of Gloucester, should be practised: (1) Rising on the balls of the toes, the toes being directed straight forwards; (2) rising on the balls of the toes, with the points of the great toes touching each other, and the heels directed out, so that the medial borders of the feet meet in front at a right angle; (3) in the same attitude, after rising on to the balls of the toes, the knees are flexed and then extended before the heels descend again; (4) while seated in a chair, one leg crossed over the other, circumduction movements of the foot are carried out; (5) while standing, the medial border of the foot is raised off the ground several times, then the patient walks to and fro on the lateral border of the foot, and in the same attitude lifts one foot over the other. These exercises should be carried out slowly and deliberately, with the feet bare, and they should be carefully supervised until the patient thoroughly understands what is aimed at. The movements should be performed a definite number of times at regular intervals, but should not be pushed so as to cause pain or fatigue. The patient should be fitted with well-made lacing boots, with the heel and sole raised about half an inch on the medial side so that the foot rests mainly on its lateral border. The additional leather, which can be applied by any bootmaker, is in the form of a wedge, with its base to the medial side, one on the sole and one on the heel. The wedge fades away towards the lateral border, and also forwards towards the tip. In time, the limbs are further strengthened by sea-bathing, cycling, skipping, and other exercises.
In cases of the second degree, the patient should be provided with a metal plate inside the boot. That known as Whitman's spring is the most popular. A plaster cast is taken of the sole while the foot is held in its proper position, and on this a metal plate, preferably of aluminium bronze, is modelled. This is covered with leather and inserted into the boot. We have found the supports devised by Scholl simple and efficient. The treatment described for cases of the first degree is carried out in addition.
In cases of the third degree, the deformity is corrected under an anæsthetic. The foot is forcibly moved in all directions so as to stretch the shortened ligaments and to break down adhesions, it is then rotated into an extreme varus position, and fixed in plaster-of-Paris or to a Dupuytren's splint. It may be necessary to have recourse to the Thomas' wrench, employed in the correction of club-foot. When the reaction consequent upon this procedure has subsided, the question of shortening or of reinforcing the tendons concerned in the support of the arch of the foot may be considered; one of the peronei, for example, may be attached to the tubercle of the navicular. We have not found it necessary to employ this procedure.
In cases of the fourth degree, in which the displacement and alterations in shape of the bones constitute an insuperable bar to correction, operative treatment may be considered, either resection of a wedge including the talo-navicular joint or forward displacement of the tuberosity of the calcaneus.
Spasmodic Flat-foot.—There are cases of flat-foot in which pain and spasm of the peronei muscles are the predominant features. If the spasm is not allayed by rest in bed and hot fomentations, the foot should be inverted under an anæsthetic; and in this position it is encased in plaster-of-Paris. Jones resects an inch of each of the peroneal tendons about 21/2 inches above the tip of the lateral malleolus; Armour and Dunn claim to have obtained better results from crushing the peroneal nerve in the substance of the peroneus longus.
Paralytic Flat-foot ([Fig. 155]).—In typical cases this results from poliomyelitis affecting the tibial muscles. When other groups of muscles are affected at the same time, compound deformities, such as pes calcaneo-valgus, are more likely to result.