FLAT FOOT

Henry Middleton Michel, M.D., Augusta, Ga.

The advantages that accrue to man from the power of walking in the erect posture are to some extent limited by certain deformities that this position is likely to produce. Savarin, long ago remarked rather irreverently, that the design of the human foot was a notable failure among the works of creation. A common example of the weakness of the foot is to be found in the condition usually called flat foot. That a study of this painful disability is of moment to the general practitioner is suggested by the fact that flat foot is so frequently mistaken for rheumatism. The bones of the foot arrange themselves into two arches; an antero-posterior or longitudinal and a transverse or lateral arch. The longitudinal arch is made up of the oscalcis behind and the scaphoid and the three cuneiform bones with the heads of the metatarsals in front. At the apex of their structure and acting as a keystone, is placed the astragalus. This arch is held up partly by the muscles of the foot and the leg but more especially by the ligaments stretched between the bones. Particularly by the short plantar ligament which completes the internal left by the approximation of the anterior surface of the oscaleis with the posterior surface of the scaphoid. The bolstering effort of this ligament is further aided by the long planter ligament running from the oscalcis to the heads of the metatarsals. The combined effect of all these factors is to lift up the inner border of the foot and to draw toward each other the two ends of the arch. The transverse arch is much less securely supported, having bony abutments on its outer side only. The curved end of the transverse arch is held

up very largely by the tendon of the peroneus longus muscle.

Bearing in mind this arrangement of the arches of the foot it is easy for us to see that if there should arrive a time when the weight to be borne is greater than the power of the arch to bear it that there will be a stretch on the ligaments and a consequent spreading of the arches. The inner border of the foot being the less supported part suffers most in this spreading out process; thus under the pressure of the body weight the astragalus is thrust inward and forward as well as downward. The rolling inward of the astragalus which causes a convexity at the center of the inner line of the foot, is in some cases the most noticeable part of the deformity. Together with this bulging of the inner surface of the foot is to be seen a flattening of the instep and a more or less marked abduction of the front of the foot.

In cases of flat foot when the bare heels are observed from behind the tendo-achilles is seen to make a sharp outward deflection from the normal perpendicular. By far the commonest cause of the purely static type of flat foot is the weakened condition of the muscles and ligaments of the foot brought about by wearing improper shoes. Feet thus weakened frequently are found to be unable to stand the strain of rapidly added flesh or the sudden change from a sedentary life to one which necessitates long hours of standing.

The symptoms of flat foot vary greatly in individual cases. Quite often one observes cases in which there is a considerable degree of deformity, but which give rise to but little pain or other disability. On the other hand individuals are seen in whom the disability seems to be out of all proportion to the amount of structural changes. The patient usually seeks aid because of pain. This pain is felt in the neighborhood of the internal malleolus or over the scaphoid and is frequently referred to the calf of the leg. Because of this more or less persistent pain in standing or walking the diagnosis of rheumatism is

often made without a thorough examination of the components of the foot. Such an examination would disclose that there is a limitation of the normal amount of adduction in the front part of the foot and that dorsal flexion and extension of the foot is somewhat limited at the ankle joint. There is a stiffness in the foot giving rise to a clumsiness and awardkness of gait, which is especially complained of in the morning on arising and after being seated for some time. An examination of the shoe usually shows that the inner side of the sole and the heel have been run-down more than the outer side. An impression of the sole of the foot shows an increased weight bearing area, a flattening out of the surface. An easy method of gaining such an impression is by painting the sole of the foot with a solution of perchloride of iron in glycerine. Place the patient's foot on a piece of paper and cause him to put the full weight down upon it. Immerse the resulting impression in a solution of tannic acid and the tracing becomes black and forms a very convenient means of following the progress of the treatment. The treatment of static flat foot aims both to develop the structures that normally preserve both arches of the feet, and at the same time to render support to the arches by some form of brace.

No treatment can be considered complete that does not attempt to accomplish both of these objects. The exercises recommended by McKenzie will be found useful.

Exercise 1. Patient sitting, leg extended and supported just above the ankle with the left hand. Place the right hand on the sole of the foot. With the thumb pointing toward the toes grasp the foot firmly, circumduct the foot slowly in the following order. (1) Extension. (2) Inversion. (3) Flexion. (4) Eversion.

This should be done with as much force as can be used without causing pain, and repeated about thirty times. The patient should then be asked to perform the same movement without the assistance of the surgeon.

Exercise 2. The patient standing, with toes in and heels out and about twelve inches apart, rise on the toes and press out slowly. Repeat fifty times.

Exercise 3. Patient standing, with feet parallel and six inches apart, raise the inner border of the foot throwing the weight on the outer border. Repeat this fifty times. This transfers the weight from the ligamentous support to the bony ridge of the outer edge of the foot and should be followed by

Exercise 4. The patient standing, feet parallel, weight resting on the outer side of the foot. Move forward and backward fifty steps keeping the feet parallel. This exercise is also valuable in throwing the weight of the body on the solid part of the lateral arch, and is a position that is frequently instictively taken by patients to relieve the intolerable pain caused by the over stretching of the ligaments.

Exercise 5. Raise the heel one inch from the ground. and walk without putting the heel down at all as if the heel were painful. This exercise can be practiced indefinitely, the patient walking for a hundred yards without letting down his right heel, and then the next hundred yards without letting down the left heel, or raising the heels when crossing the street or other plans which readily suggest themselves. A little practice will enable him to walk in this way without limping or otherwise attracting attention. These exercises should be carefully performed twice daily for many months. In the mildest cases such exercises are sometimes sufficient to effect a cure, but in those cases of long standing of a severer type in which there is a rigidity of the foot it is necessary to overcome this rigidity by a forcible over correction of the foot under general anaesthesia. The foot is then so forcibly manipulated as to break up all adhesions due to the structural changes. After the foot has been so manipulated as to have gained the full range of normal motion it is then put up in a carefully applied plaster-of

paris bandage in an extremely over-corrected position, that of Talipes Varus. The patient is encouraged to walk in this apparatus, the assumption being that weight bearing will further over-correct the deformity.

After the plaster bandage has been worn for three or four weeks, it is then removed from the foot and a cast of the foot is taken over which a flat foot brace is fitted. The brace which I have found most generally useful is that devised by Whitman, of New York. This brace furnishes an unyielding support to the parts of the foot needing support but allows freedom of motion to the front of the foot. It covers and protects the astragaloscaphoid junction rising well above the scaphoid. The external arm covers the calcaneo cuboid junction and the outer aspect of the foot to a height sufficient to hold the foot securely. The sole part provides a firm, comfortable support. The brace is made out of eighteen or twenty gauge steel. It may be nickel-plated which makes a smooth finish or galvanized which is rather more durable. This brace requires no attachment to the shoe and therefore, may be changed from one shoe to another. Not only does it hold the foot laterally and from beneath but as Whitman says, "there is a slight element of suggestiveness in the leverage exerted which is a distinctive feature of this brace as contrasted with the simple sole plates found in the shoe shops..

An easy method of making a plaster-of-paris cast on which the brace is to be fitted is as follows:

Seat the patient in a chair; in front of him place a stool somewhat lower in height, on which he is to place his foot. On this stool place a cushion over which newspapers are placed to protect it. Putting about one quart of cold water in a basin, sprinkle plaster-of-paris on the surface until it does not readily sink to the bottom and stirring it constantly allow it to become of the consistency of very thin ice cream, Then pour it upon the newspaper. Flexing the patient's knee, the outer side