The diagnosis of rheumatism is frequently made in flat foot, and is often the source of much misdirected treatment. Rheumatism should be diagnosed only in connection with unmistakable symptoms of rheumatism in the upper extremities.
So-called “rheumatic” pains in the knees and hips may be secondary to flat foot.
Prognosis. As a rule, this condition does not recover spontaneously. Under ordinary conditions, uncomplicated cases should be at once relieved by proper treatment, and in time should be cured.
Unfavorable factors are: great weight; disease of the ankle-joint; the presence of bony spurs under the os calcis.
The prognosis is more favorable in young adults than in persons of advanced age. Patients, who without relief have worn the ordinary supports sold at the stores will, as a rule, manifest extreme sensitiveness as to the fit of any of the supports which may be applied.
Treatment. The foot must be restored and held in its normal position and measures must be adopted to quiet local irritability or inflammation, and to strengthen the muscles. The best treatment does not consist in the permanent wearing of a flat-foot support; the support should be regarded in the same light as one uses a crutch in a fracture of the leg.
As a preliminary to all treatment, the use of proper shoes must be insisted upon. A shoe should be as wide in front, as the unshod foot, when bearing the weight of the body.
Supports. Flexible supports may be made of boiler felt; one objection to these is their liability to stretch. They are of service in young children, in mild cases, and in convalescent cases where it is desirable to have the patient use a flexible instead of a stiff support in order to bring the muscles into play.
Rigid supports are best made of tempered spring steel (18 to 20 gage), forged hot to fit a cast of the foot. They may also be made of phosphor-bronz, celluloid or aluminum.
The shape of the plate is largely a matter of judgment. The easiest way to determine the shape of the plate to be used in a given case is to have the patient stand with the operator’s hand under the inner side of the foot; the operator then places the foot in the normal position and notes where the pressure must be applied to secure the proper correction; when the anterior part of the foot is flattened, a slight dome must be constructed in the front of the plate; when the os calcis is clearly tilted over, the plate must have two flanges at the heel to hold it in place. In general, the plate must reach forward to a point just behind the great-toe joint, and must furnish support as far as the front of the heel. The plate should be higher on the inner side, and a flange formation is generally necessary to accomplish this. An outer flange prevents the foot from slipping off the outer side of the plate. When the foot no longer requires support, the plate should be gradually discontinued.