What Is a Congenital Malformation?

Congenital foot deformity refers to abnormalities in the shape or structure of the foot. Normal human foot shape is maintained by the symmetric external and internal muscles. Flat feet with congenital bone and muscle development abnormalities, malposition of varus in the mother's womb before birth, cerebral palsy caused by birth trauma can all cause congenital foot deformities. ^[1]

Congenital foot deformity

Congenital foot deformity refers to abnormalities in the shape or structure of the foot. Normal human foot shape is maintained by the symmetric external and internal muscles. Flat feet with congenital bone and muscle development abnormalities, malposition of varus in the mother's womb before birth, cerebral palsy caused by birth trauma can all cause congenital foot deformities. ^[1]

Causes of congenital foot deformity

The causes of congenital malformations are genetic factors, environmental factors, and the interaction between the two. Among them, 25% are birth defects caused by genetic factors, 10% are environmental factors, and 65% of genetic factors interact with environmental factors and unknown causes. .

1. Genetic factors and congenital malformations

Congenital aberrations caused by genetic factors, including chromosome aberrations and gene mutations, account for 25% of congenital aberrations. Chromosome aberrations include abnormal numbers of chromosomes or structural abnormalities. The chromosomes are pairwise opposite, and the reduced number can cause congenital malformations, which are often associated with haplotypes. The haplotype embryo of the plant chromosome can hardly survive, and only 3% of the haplotype embryo of the sex chromosome survives, but there are abnormalities, such as congenital ovarian hypoplasia, that is, Turner syndrome (45, 0X). An increase in the number of chromosomes can also cause malformations, which are more common in trisomy, such as the common congenital type, which is caused by chromosome 21. Trisomy of sex chromosomes (47, XXY) can cause congenital testicular hypoplasia. Chromosome structural aberrations can also cause deformities, such as the deletion of the short arm end of chromosome 5, which can cause "meow syndrome". Gene mutations cause a few abnormalities, such as cartilage dysplasia, polycystic kidney disease, and multiple fingers (toes), which mainly cause metabolic genetic diseases.

2. Environmental factors and congenital malformations

The environmental factors that can cause congenital malformations are collectively called teratogens, accounting for 10% of congenital malformations. The environment that affects embryo development has three aspects, namely the external environment around the mother, the internal environment of the mother, and the microenvironment around the embryo. Some of the teratogenic factors in the external environment can directly affect the embryo by changing the internal environment and microenvironment, while others can indirectly interact with the embryonic body by changing the internal environment and microenvironment. Environmental teratogenic factors include biological, physical, chemical, and pharmaceutical.

Physical teratogenic factors have been identified currently: radiation, mechanical stress and damage, high temperature, etc .; in the industrial "three wastes", pesticides, food additives and preservatives, there are some teratogenic chemicals, they are some Some polycyclic aromatic hydrocarbons, some nitroso compounds, some alkyl and benzene compounds, pesticide diquat, lead, arsenic, cadmium, mercury, etc. The sedative "stop reaction" that caused a large number of limb deformities in Western Europe in the 1960s is an example of chemical teratogenicity.

3.Other teratogenic factors

Other teratogenic factors include alcoholism, heavy smoking, hypoxia, and malnutrition.

Viral infection is the main type of intrauterine infection. Due to the barrier effect of the placenta, some macromolecular substances are generally not easy to pass through the placenta, while viruses with a small molecular weight and some parasites can infect the embryo or fetus through the placenta. Infected with a variety of pathogenic microorganisms and transmitted to the fetus through the mother, can cause the fetus to cause various deformities. The teratogenic effects that have been identified on human embryos include: rubella virus, cytomegalovirus, herpes simplex virus, toxoplasma, Treponema pallidum, and hepatitis B virus. The harm of AIDS to the fetus has caused concern. ^[1]

Congenital foot deformity

Introverted foot: Due to the paralysis of the peroneus longus muscles, you can only carry weight and land on the outside of the foot when walking and standing, the foot is tilted inward, and the Achilles tendon is also deflected inward.

Horseshoe feet: Also known as sagging feet and pointed feet. Caused by paralysis of the tibialis anterior muscle. When standing, you can only land on the front foot, the ankle joint is excessively flexed, the heel cannot bear the ground, and the Achilles tendon contracture becomes shorter. Horseshoe foot and varus foot often coexist.

Congenital foot deformity

Valgus foot: caused by paralysis of the anteroposterior muscles of the tibia, as opposed to the shape of the varus foot. It can only land on the inside of the foot and bear weight.

Toe-up foot: also known as heel foot, heel foot. More common in the gastrocnemius and soleus muscles due to paralysis and congenital malformations, standing, walking, weight bearing with the heel, the toe raised, ankle dorsiflexion.

Arched foot: The longitudinal arch of the foot is significantly higher than normal, and the angle of the arch is reduced when measured. No discomfort. It is caused by the imbalance of the internal and external muscles of the foot.

Hammer foot: Caused by excessive relaxation of the transverse arch of the foot.

Flat feet: A flat foot is the disappearance of the arch of the foot. The arch of the foot is composed of the foot bones and ligament muscles. There is a transverse arch and a longitudinal arch under normal conditions. The small bones of the human foot are stacked into an arch and become the arch of the foot. When the human body is standing, walking, and bearing weights, not all of the feet are bearing weight. The sacrum and heel are the main weight bearing. The arch of the foot is often suspended to cushion shocks, protect the brain and internal organs, and make people have good bouncing properties. If the arch formation is poorly developed or due to various injuries, the arch disappears to form a flat foot. Some are hereditary. Some flat feet have no discomfort, while others can cause pain and affect walking.

In addition, foot scar contracture caused by various trauma can also cause foot deformation.

Congenital horseshoe varus is a common orthopedic congenital malformation in children. Its incidence is 1/1000, boys are twice as high as girls, and unilateral slightly more than bilateral. Its incidence is related to bone, muscle, nerve and genetic factors. After birth, one-foot or two-foot horseshoe varus deformity occurs, that is, small heel, heel inversion, forefoot adduction, each toe is deflected inward, and calf malformation is often combined. As the age increases, the deformity gradually increases. Especially after walking with a load, because the lateral edge of the back of the foot touches the ground, a local rash often occurs. ^[1]