How to treat knee deformities in children: knock knees and bow legs

Genu valgum (knock knees) and genu varum (bow legs) are common postural deformities in young children, in which the head of the knee points inwards and the legs point outwards. It varies in seriousness and sometimes requires minimally invasive surgery if it has not corrected itself through growth and development.

From the age children learn to walk until they are approximately two years old it is common to see the legs become genu valgum (knock knees). From of the age of three, their legs usually adopt the genu varum (bowed leg) form. This posture is usually maintained until the age of seven or eight, when the legs return to their normal position. Therefore from the age of eight any child with knock knees of bowed legs may require treatment.

Complications that knee deformities in children and adolescents can cause

Knock knees and bow legs alter the mechanical axis of the knee, which overloads the internal or external part of the knee. This can lead to pain, meniscal injury or osteoarthritis in adulthood.

What are the kind of deformities in the knees of children and adolescents?

It is important to differentiate the two groups of deformities:

1. Postural deformities – where there is an exaggeration of the posture and with knock knees or bow legs. Generally, radiological and clinical studies find no cause in bone development or any type of metabolic disease: that is, they are healthy children that develop bowed legs or knock knees.
2. Bone disorder (pathological) deformities – these are children who have deformed knees, where there is also an alteration of the growth of these or other joints of the body. These are alterations caused by congenital or genetic disorders.

Treatment to correct knock knees and bow legs in children and adolescents

Hemi-epiphysiodesis (guided growth control) is a minimally invasive surgical procedure which is a reliable treatment for knock knees and bow legs.
Hemi-epiphysiodesis is a technique used to promote straightening of the legs. It uses special tension plates with two screws that are placed through a small incision in the child’s knee, without damaging the growth cartilage. The child stays in hospital one day and begins to walk the day after the procedure, and after 15 days the child can lead a normal life. The improvement in the knee position is monitored every four months. When sure that the correction is complete, the plates are removed through a small incision in the same wound, and growth continues.

Post-operative care in the treatment of knee deformities

The child is not required to wear a cast following the surgery and it normally takes 12-18 months for normal alignment to achieved. This can vary and the progress of a child’s growth which needs to be monitored.