Knocked knees (genu valgum)

What are knock knees?

Knock knees is a condition in which knees touch (or “knock”) one another even when the ankles are apart. It is a common condition in healthy children in early childhood and can be part of normal growth and development, usually worst at the age of 4, and ‘normalised’ by the age of 7. However, when it occurs outside of normal development or is more severe than normal, it may be due to an underlying disease.

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Symptoms

Most often this condition is asymptomatic
Appearance of the ankles further apart than normal when the knees are together. This usually becomes apparent from 2 - 3 years old.
Unusual walking pattern with outward rotated feet – hip, knee, ankle or foot pain may result from this abnormal gait.
Difficulty running
Severe cases may cause knee pain or limping

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Causes

Physiologic – normal part of growth and development (most common)
Being overweight or obese
Trauma
Infection
Rickets
Skeletal dysplasia
Benign tumours or tumour conditions

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When should parents be concerned?

Your child has a limp or pain in their legs
Difficulty in walking
Only one leg is affected, or one leg is significantly worse than the other
Knock knees are severe
Getting worse over the age of 5 - 6 years old
Persisting after the age of 10 years old
Your child is unusually short for their age
Develops later in childhood
Has a known underlying condition

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Diagnosis

Through physical examination of the legs and gait. Measurements of the distance between both ankles may be taken and monitored over time.

Your doctor may arrange x-ray imaging for further assessment or confirmation of diagnosis.

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Management and treatment

Treatment is rarely needed and most commonly as your child grows their legs will straighten. Majority will grow out of the condition by 7 years of age. Splints, bracing and special shoes are not recommended.

Surgery is only required if a severe deformity is present or persisting, the deformity is asymmetric, there is significant difficulty with pain or mobility which could be improved.

While your child is still growing (before the age of 13 - 14 for girls and 16 - 17 for boys), using guided growth (small metal plates or screws over the growth plate) is a small, usually day case procedure, to help correct knocked knees over time.

After your child has finished growing, realigning bones by cutting them is a much bigger operation to correct the position of the knees.