Orthopedics - Oleksa A.P. 2006

Congenital and acquired deformities of the lower limb
Lower limb malalignment

At birth, infants keep their legs flexed at the knee joints due to the fetal position in the womb, and they are unable to extend them. Only in hypotonic infants can the legs be easily straightened. This condition persists until nearly two years of age, as the body's center of gravity is low and the Muscles are still weak.

At the same time, newborns exhibit a varus alignment of the knee joints, which depends on the degree of medial bowing of the Tibia. When the child begins to stand, this varus curvature may initially remain unchanged before transitioning into valgus, as the child reflexively seeks a wider base of support due to the weakness of the limb and trunk muscles.

An affected child, while placing their feet wide apart, positions the knees closer to the midline of the body, which leads to a valgus deformity. As the child grows and Muscle strength increases, their physical activity rises, and the alignment of the lower limbs gradually normalizes. This normalization process takes three to four years.

However, this process is sometimes disrupted due to congenital anomalies (such as Changes in the shape of the shin bones, Congenital pseudarthrosis of the tibia, or fibular defects, etc.) or acquired conditions (Rickets, Blount's Disease, periarticular Inflammatory Diseases, tumors, etc.). There are also cases of inherited knee deformities.

These pathological factors can cause various types of deformities in the knee joint region and deviation of the lower leg in different planes.

Most commonly, deviations of the lower leg occur in the frontal plane relative to the normal axis of the lower limb — Genu Valgum (knock-knee deformity) or genu varum (bow-leg deformity).

Less frequently, patients present with lower leg deviation in the sagittal plane, resulting from a hyperextended knee (genu recurvatum) or a flexed knee (genu flexum).

Sometimes, There is a simultaneous combination of deformities in both the frontal and sagittal planes: lateral Rotation of the lower leg produces genu laterocruratum, while medial rotation results in genu mediocruratum, both of which are often associated with genu valgum.