Causes:
Physiological – As mentioned before, bow legs are normal below 18 months of age. Thereafter as the child continues to grow the bowing begins to improve slowly. By the age of 3 to 4 the deformity usually gets corrected.
Blount’s disease – This disease results in bowing of legs due to abnormality of the growth plate of the upper part of shinbone known as tibia. Growth plates are the growing end of the bones. It is diagnosed after the child is 3 to 4 years old.
Rickets – Rickets is a group of diseases that occurs due to deficiency of vitamin D. Rickets is characterized by bow legs and other bony deformities. Most commonly rickets occurs in children due to deficient intake of vitamin D.
Signs and symptoms:
The bony deformity becomes visible when the affected child walks or stands. The uncommon walking pattern of the child is the commonest symptom. Bow legs usually do not cause any pain. However, persistent and severe bow legs cause discomfort to other bony structures like spine and hip.
Test and diagnosis:
The doctor at first asks questions to the parents regarding the development of the child. This is followed by physical examination of the child. Physical examination often suggests bow legs. If the doctor suspects an underlying disease, necessary laboratory tests are done. The doctor always asks for an x-ray of the affected legs to evaluate the severity and extent of bowing.
Treatment:
If the bow legs persist after 3 to 4 years or an underlying disease is detected, treatment is undertaken.
Medical and non-surgical treatment–
In cases of physiological bow legs, no treatment is required. The parents are reassured by the doctor and spontaneous resolution takes place by the age of 2 years. Continuous followup is advised for borderline cases. Children with Blount’s disease need treatment with a brace. Children with rickets need medical management by a specialist doctor. Additionally, they need advice and regular followup by an Orthopedic surgeon.
Surgical treatment –
If the bony defects persist in children with bow legs even after medical and nonsurgical treatment, surgery is required to correct the bowing. Two types of surgery is advocated to correct bony deformity of the legs.
Guided growth: Growth of the healthy part of the growth plate is stopped and that of the abnormal part is promoted. This allows straightening of the legs.
Tibial osteotomy: The shinbone (tibia) is cut and reshaped to correct the deformity. Then bone is fixed with screws and plate.
In both surgeries a cast is applied to promote healing of the bone. Crutches may be required for a few weeks to prevent weight bearing on the limb. Later, physical therapies are advised for complete recovery of range of movements and regular activities.
Prevention
The parents need to be vigilant about appearance of any bony deformity in legs of their child. The child must be given adequate amount of vitamin D in diet or vitamin D supplementation to prevent development of rickets.
