The long bones in the lower limbs contribute to the longitudinal growth of the child. The growth of child follows a typical pattern till skeletal maturity. Any variations in this growth pattern can result in deformities. Bow legs are one of the common conditions encountered in growing child.
Bow legs is a condition in which the legs are bent outwards. When a child with bow legs stands with feet together there is wide gap between the knees and lower legs (shin bone). Bowing can be either in one or both legs. Bowing may appear exaggerated in standing and walking position.
Physiological bowing (Physiological Genu varum):
Bowing of legs is a normal variation in growing child up to the age of 2 years. This is called as physiological bowing or physiological genu varum. The bowing starts to get corrected by 2 years of age and have normal appearance by age of 3 to 4 years.
Rickets is metabolic bone disease caused by deficiency of Vitamin-D in childhood. Bow legs is one of the many deformities seen in rickets. Nutritional rickets is more common in developing countries like India, Africa etc. Rickets can be inherited in some genetic conditions in which there is poor absorption of Vitamin-D.
Blount’s disease is a condition in which there is abnormality of the growth plate in upper shin bone (Tibia). It usually occurs in toddlers, as well as in adolescents. In case of children below two years it is difficult to differentiate between Blount’s and physiological bowing. If the bowing is worsening above 3 years and X-ray is showing disturbances in growth plate the diagnosis of Blount’ s disease can be established.
Most of the complaints are by the grand parents or parents as the child starts standing or walking.
-Different walking pattern as compared to other children.
-Frequent falls or tripping
-Deformity or outward bending of one or two legs
-Bowing more on standing or walking
-Turning in of feet (in-toeing) can be commonly associated with bow legs.
Examination by doctor and investigations:
-Child evaluation with birth history and enquiry on developmental milestones.
-Physical examination of hips, knees, legs and foot.
1.Child under 2 years : If you doctor notices symmetrical bowing and child is in good health, it is a physiological genu varum.
2.Child under 2 years : If your doctor notices that one leg is severely bowed as compared to the other leg, he or she may advise you to get an X-ray. X-ray can show features of Rickets or Blount’s disease.
3.Child above 3 years : If your doctor notices bowing of both legs or one leg he or she may order an X-ray. If the X-rays shows signs of Rickets he or she may order some blood investigations.
1.Physiological bowing (Physiological Genu varum):
a.Non-operative treatment: Physiological genu varum corrects spontaneously as child grows. The legs become normal by the age of 3 to 4 years.
b.Operative treatment: In rare cases physiological genu varum may persist during adolescence. If the bowing is significant enough causing cosmetic issues, surgery to correct deformity should be done.
a.Non-operative treatment: Rickets is caused by deficiency of Vitamin –D. If child is diagnosed with rickets, your doctor will investigate for deficiency of Vitamin-D and treat the deficiency. The deformity might get corrected as the child grows and deficiency is addressed.
b.Operative treatment: Surgical correction is necessary in those which the deformity persists despite correction of vitamin-D deficiency.
a.Non-operative treatment: If the condition is diagnosed early application of brace can help in decreasing the deformity. However if the condition is diagnosed in adolescents bracing of legs is ineffective and needs surgical correction.
b.Operative treatment: If the deformity is progressive despite using braces, surgery to correct the deformity should be done by the age of 4 years. Surgery corrects the deformity and prevents further damage of growing end of shin bone (Tibia).
1.Femoral or Tibial osteotomy :
Thigh bone (Femur) is cut just above the knee joint. The bone ends are realigned to correct the bend and fixed with wires or plates.
Shin bone (Tibia) is cut just below the knee joint. The bone ends are realigned to correct the bend and fixed with wires or plates. After the surgery child is put on the plaster cast till the bone heals. These implants are removed when the cut ends of bone are healed.
2.Guided growth arrest:
The culprit is the growth plate at the upper end of shin bone. The inner end of the growth plate is damaged as compared to the outer end which results in deformity. In this procedure growth of outer end of growth plate is stopped temporarily, allowing the inner end growth to match with outer end growth. This procedure can gradually correct the bend as the as the child grows.