How the axis of the legs changes with age
The shape of a child's legs naturally changes. Newborns have a physiological O-shaped position of the legs; by one and a half to two years the legs straighten, then the pendulum swings in the other direction: at three or four years old, many children look noticeably X-shaped, and this scares parents. By the age of six to eight years, the axis gradually comes to a slight valgus, which is also characteristic of adults, and in women it is slightly more pronounced due to a wider pelvis. Therefore, the main guideline is not a one-time examination, but age-appropriateness and dynamics.
- Up to 1.5–2 years - physiological O-shaped position
- At 3–4 years - physiological valgus
- By 7–8 years, the axis is close to the adult one
- Slight valgus in adults is normal
- Assess dynamics, not just one dimension
When the deformation is not physiological
Several signs allow you to suspect the disease. Unilateral deformity is almost always pathological and requires examination: it occurs after a displaced fracture, damage to the growth plate, or inflammation of the bone. Bilateral severe deformity in combination with short stature makes one think of rickets, including its hereditary forms that are resistant to regular vitamin D, and skeletal diseases. The progression after eight years and the persistence of a large distance between the ankles in a teenager are also alarming.
- One-sided deformation
- Short stature and developmental delay
- Progression after 8 years
- Deformity after bone injury or infection
- Vitamin D deficiency and rickets
- Hereditary skeletal diseases
- Severe obesity
What does this threaten?
Physiological valgus in a child goes away without a trace. Severe and persistent deformation changes the distribution of the load: the outer part of the knee joint is overloaded, the internal ligaments are stretched, the foot flattens and falls inward. In adolescents and adults, this manifests itself as pain in the knees after exercise, rapid fatigue, instability, and in the long term increases the risk of arthrosis of the outer part of the knee joint. The gait changes, the hip joints and lower back suffer. That is why severe deformities are corrected while the child is growing.
- Overload of the outer knee joint
- Sprained internal knee ligaments
- Flat feet and inward roll of the foot
- Knee pain after exercise
- Fatigue when walking
- Increased risk of future osteoarthritis
Survey
The doctor measures the distance between the inner ankles with the knees together, evaluates the child’s growth along the curve, the symmetry of the legs, the condition of the feet and gait. If the picture corresponds to the age and the deformation is symmetrical, additional studies are not needed - observation is enough. In case of severe, asymmetrical or progressive deformity, an X-ray of the legs with a load in a standing position is prescribed to measure the axis of the limb. Vitamin D, calcium, phosphorus and alkaline phosphatase are tested in the laboratory to rule out rickets and mineral metabolism disorders.
- Measuring the distance between your ankles
- Assessing leg height and symmetry
- Examination of feet and gait
- X-ray of legs with a load with severe deformity
- Vitamin D, calcium, phosphorus, alkaline phosphatase
- Consultation with an endocrinologist for short stature
What to do
In most cases, observation with a re-examination after six months or a year is sufficient. Orthopedic shoes and insoles do not straighten the axis of the legs, but they help with concomitant flat feet and reduce foot fatigue. Normalization of weight, active games, swimming, strengthening the muscles of the thigh and lower leg are useful. If vitamin D deficiency is confirmed, it is replenished as prescribed by a doctor, and for hereditary forms of rickets, treatment is selected by an endocrinologist. Severe deformity in a growing child is corrected by sparing surgery on the growth plate; in adolescents and adults, by osteotomy.
- Follow-up observation
- Normalization of body weight
- Exercises for thigh and lower leg muscles, swimming
- Insoles for concomitant flat feet
- Replenishment of vitamin D deficiency as prescribed by a doctor
- Treatment of rickets and metabolic diseases
- Controlled correction of the growth plate in children
- Corrective osteotomy in adolescents and adults