CLUB-FOOT (PES VARUS) This is a condition in which the foot is fixed in a supinated posi tion, the inner border turned upward and the outer border turned down ward. The end of the foot is inverted and at the same time tilted downward.
Congenital club-foot (pes yarns congenitus) is the most frequent of all deformities. Bessel-Hagen's statistics show that it occurs once in every twelve hundred births. It is found more frequently in boys than in girls and is bilateral in over half the cases. More than one-tenth of the cases arc combined with other deformities.
Etiology.--A large number of cases can be traced back to primary developmental deformities. The etiological factor seems to be inherited. Joachimsthal reports a case where a father and his three children were all afflicted Nvit h club-feet.
Inherited narrowness of the uterus, as well as other individual condi tions, induces the formation of club-feet; although it would correspond more to the modern biological way of reasoning to look upon these fac tors as exciting causes only, than to assume that one or both feet had been forced into such a narrow space or loop as to become firmly fixed in that 011C position.
Cases which show Volkmann's pressure points and constriction in the pathological position after birth are of rare occurrence.
Not infrequently a club-foot is combined with a flat-foot on the opposite side, due to pressure in that position in utero, and the feet retain the same position after birth.
From that pathologieal-anatomical standpoint it is evident that fixation of the foot in a certain position must cause corresponding changes in the hones and ligaments and force the muscular apparatus to adapt itself to the new functions. The bones are almost pressed together on the concave side, diminished in size and condensed in tissue. On the convex side they appear swollen, enlarged, and rarefied. The neck of the astragahts is longer on the outside and points inwards and obliquely. The anterior process of the calcaneus is elevated and the upper articulat ing surface inclines obliquely in a median direction. The entire longi
tudinal axis of the valcaneus shows a concavity on the inner side, and its articulating surfaces incline in the same direction and the cartilaginous covering is displaced accordingly.
When the conditions persist for a long time the disused cartilages disappear entirely and obstructions form which do not allow a return to the normal position. The further growth tends to increase the deformity.
The ligaments naturally adapt themselves to this position and the development of the muscles also undergoes changes corresponding to the restriction of motion. The muscles of the calf of the leg are affected the most, for little work is left for them as the foot is generally in a position of extreme plantar flexion. The greater part of the gas trocnemius muscle moves upward, just far enough to permit of suffi cient contraction to perform the small amount of motion allowed by the fixation.
The symptoms are derived from the pathological anatomy. The foot is supinated, the inner border elevated and the outer lowered. In addition there is adduction of the front part of the foot, which is turned inward to the extent of 90° or more. Necessarily combined with these symptoms is a plantar flexion resulting in distortion of the foot and marked exaggeration of the arch. This eau be readily seen from an impression of the sole of the foot.
Locomotion is restricted on account of the range of motion. The ehililren walk on the outer border of the foot and the inward rotation of the foot by rotating the leg out wards at the hip. The knee tends to become more rigid and fixed so that the leg is used as a stilt. The quadriceps muscle becomes atrophied from disuse (see Small ness of patella, page 119). The pathological position increases with the weight of the body, and in the more pronounced eases the patients walk almost on the dorsum of the foot, the entire sole facing backward and the toes inward and even backward (Figs. 53, 51, 55).