Knock Knees in Children (Genu Valgum)
Knock knees are common during childhood growth.
They often improve naturally, but in some children the alignment persists or becomes excessive.
They may be associated with:
What symptoms do knock knees cause?
Children may complain of pain around the knees, especially during activity.
Inner (medial) knee pain
Usually caused by repeated stretching of the inner knee ligament.
Outer (lateral) knee pain
More common in older children and may occur due to increased joint stress.
If untreated, this can rarely lead to cartilage injury, meniscal damage, or early joint wear.
How do flat feet contribute to knock knees?
Flat feet cause the heel to tilt outward (heel valgus).
This shifts the leg alignment inward over time, gradually producing knock knees.
Vitamin D deficiency may worsen this process by affecting bone strength.
Clinical Assessment
The severity is measured using the intermalleolar distance
(the gap between the ankles when standing with knees touching).
What investigations are needed?
Blood Tests
To assess:
Standing long-leg X-rays
Taken with kneecaps facing forward
These:
Do all children need surgery?
No.
Most children are treated without surgery first.
An operation is only considered if the deformity persists despite appropriate treatment.
Non-operative treatment
Ideal vitamin D level in growing children: >75 nmol/L
Treatment is followed by repeat blood tests after at least 3 months.
Weight management may significantly improve symptoms and alignment.
Dietitian referral may be helpful.
Follow-up
Children are usually reassessed after about one year.
X-rays are typically performed only if surgery is being considered.
When is surgery required?
Surgery is considered if:
Guided growth (hemi-epiphysiodesis)
This is the most common surgical treatment.
A small plate is placed across one side of the growth plate to gently guide the leg to straighten as the child grows.
If flat feet are severe
Flat foot correction may also be required.
Non-operative
Operative (rare)
Key message for parents
✔ Knock knees are common during growth
✔ Many improve with treatment of vitamin D and flat feet
✔ Surgery is only needed in persistent cases
✔ Guided growth corrects alignment gradually and safely
