Genu valgum is also known as knock knee is an  angular deformity of the knee  where the leg is bend outside. It  can be primary where no cause is identified, or secondary to underlying disease.

Underlying diseases – rickets ( Vitamin D resistant / renal ), bony dysplasia, growth arrest due to trauma or infection.

Physiological valgum

when a child is born the legs are bend inward (varum ) till the age of one years, beyond that there is exaggerated valgum till the age of 3-4 years. The legs attains the ‘normal valgus’ by the age of 9-10 years.

Investigations- Always rule out any underlying disease associated with the valgus. A long leg X-ray i.e Hip to toe stitch view is taken in standing position for proper planning and exact localization of the deformity. MRI with cartilage mapping is often required if growth arrest is suspected.

Treatment

Diagnosis and treatment of the underlying associated disease takes a priority over correction of the deformity. Once the underlying disease is controlled then surgery can be proceeded.

Temporary hemi-ephysiodesis

is the current ‘treatment of choice’ it is a method which works on the principle of utilising the growing potential of a child. A small plate named ‘8’ plate is applied across the physis to temporary stop the growth of one side, on the other-hand the other side of the growth continues and in due course straightens the leg.

Osteotomy

if the growing potential has stopped then correction is done by cutting the bone and straightening the leg.

Role of brace in correction of the deformity– in small child ‘genu-valgum’ brace can be applied for small deformities.

13 years old boy with Bilateral Genu Valgum corrected by growth modulation / temporary hemiephysiodesis using ‘8 plates’

15 year old girl with bilateral Genu Valgum treated with corrective osteotomy