Genu valgum (Knock knees)

What is genu valgum?

Genu valgum is the medical term for knock knees, where the knees angle inwards so that they touch or nearly touch while the ankles remain apart. A degree of knock knee is a normal stage of development in young children, typically most noticeable around the ages of three to four, and it usually corrects on its own with growth. Knock knees need assessment when they are severe, only on one side, persist beyond the usual age, or are getting worse, as this can point to an underlying cause.

Signs and symptoms

• Knees that angle inwards, with a gap between the ankles when the knees are together

• An awkward or “knocking” gait

• In some children, knee pain or tiredness with activity

• Occasionally a sense that the kneecaps are less stable

How is it diagnosed?

Assessment involves a clinical examination, measuring the gap between the ankles and observing the gait. Where the knock knee is marked, asymmetrical or persistent, standing X-rays are used to measure the alignment and to look for any underlying bone or growth condition.

What causes it?

Most often it is idiopathic, i.e. no obvious cause is identifiable. 

It can also result from 

Trauma- affecting the growing area of the bone

Infection- affecting the growth plate

Specific fractures such as affecting the top of the tibia (Cozen's fracture)

Treatment options

Most physiological knock knees need only reassurance and observation, as they correct with growth. When the deformity is significant and persistent, particularly in older children, treatment options include 

Guided growth (a small procedure that gradually straightens the leg by steering the remaining growth) using special 8-plates or a screw.

Corrective osteotomy. Usually reserved for older children with severe deformity. Any underlying condition is treated alongside.

Outlook

The great majority of children need no treatment. For those who do, correction at the right time gives good alignment and function.

When to seek advice

If your child’s knock knees are severe, present on one side only, getting worse, persisting into later childhood, or causing pain.

This information is for general guidance only and is not a substitute for a consultation with Mr Wadia. If you are worried about your child, please seek medical advice