Careful inspection usually reveals either a mild degree of flat-foot, or of distortion by which the anterior part of the foot is broadened and held in a depressed position—or else the dorsal part of the foot is depressed behind the anterior part; there is also usually limitation of dorsal flexion of the foot and plantar flexion of the toes.
Morton, who first described the affection as having a peculiar type of its own, thought it due to entanglement of the external plantar nerve between the heads of the fourth and fifth metatarsal bones, and recommended for its relief excision of the head of the fourth of these. The etiology of the affection is not always apparent, but it is sometimes due to what has been described as a non-deforming type of club-foot, while in practically all other instances it is in some way connected with the use of badly fitting footwear.
Treatment.
—Without proper treatment it does not subside. A really weak and pronated foot should be supported with a proper plate and elevation of its inner border, while a short gastrocnemius should be stretched. Only in extreme cases or when these milder measures have failed need resort be had to Morton’s suggestion and excise the head of the fourth metatarsal.
3. Talipes Equinus.
—In this condition the equinus position is simulated, and the patient walks upon the anterior part of the foot only, perhaps even upon the ends of the metatarsal bones. While the congenital form is extremely uncommon the acquired form is that which commonly occurs. Appearing thus in all possible degrees it may in mild cases cause merely a slight limp, while the extreme cases cause a pronounced deformity and alteration in gait. The actual condition is one of shortening of the tendo Achillis through contraction of its component muscles, with corresponding change in shape of the bones of the foot. There is also more or less shortening of the plantar aponeurosis, and depression of the astragalus, which is drawn down upon the calcis ([Fig. 265]).
Causes.
—Perhaps the most common cause is paralysis, either of infantile or cerebral and spastic type, of the anterior muscles of the leg, the condition being simulated sometimes in hysteria. The spasm which follows disease of the ankle-joint may also produce it. It may be the result of muscle contraction after fractures or even after certain fevers, the foot dropping naturally into this position and remaining there altogether too long. Hence may be seen the necessity for putting the foot in the right-angle position whenever the lower limb is dressed in plaster or other rigid dressings after fracture. Talipes equinus may also be due to injury to and loss of power in the anterior muscles of the leg, or it may be compensatory, as when one leg is longer than the other. In any of these events the body weight is borne on the ball of the foot, and some degree of arching of the foot, which may be excessive, is sure to occur.
Treatment.
—In the milder cases, when seen early, it may be sufficient to thoroughly and repeatedly stretch the sural muscles, but, in the more severe forms, tenotomy of the tendo Achillis, with subcutaneous or perhaps open division of the plantar structures, will be needed. In paralytic cases [tendon grafting] (q. v.) will be required, probably with one or more of the measures mentioned above. In some instances nerve grafting might be profitably employed. After recovery from operation, braces adapted to each particular case will in all probability be required, at least for a time.