Knock Knee

In this condition when the legs are brought together then the knees will touch each other and the ankles will be separated. The normal intermalleolar distance is usually less than 10 cm.

Causes

1. Physiological genu valgum. This is seen in all children between 3-6 yrs. of age. It will correct over a period of time. The lower end of femur is the common site of origin of genu valgum
2. Pathological conditions. Renal osteodystrophy, dysplasia, physeal injury

Indications for surgery

1. Intermalleolar distance more than 10 cm
2. >15-20 deg valgus

Operative procedures

Surgery.
A) Hemi epiphysiodesis (growth modulation). Staples or ‘8’ plates can be used to temporarily stop the growth of one side of the growth plate so that gradual correction occurs over a period of time. It is a small surgery and does not require plaster. The child can be mobilized once the pain decreases
B) Osteotomy and correction. This is performed in older children in whom the growth has stopped. Bone is cut and an implant is placed to correct the deformity.

Pre-operative clinical photo of a child with genu valgus
Post-operative clinical photo of child 1 year after surgery