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Knock Knees

Knock knees is an angular deformity of the legs in which the knees touch each other but the ankles are spread apart. This is also known as “genu valgum." Typically during childhood and especially during early grade school, knock knees is a normal part of growth. This is called “physiologic genu valgum."

During infancy and toddler years, bowlegs or genu varum is common. During the age of 18–24 months, the bowing improves and the legs appear more straight. Around the age of 2–3 years, parents may notice that the knees begin to touch presenting as knock knees. The most common age to see knock knees is around age 4. By the age of 7 or 8, there should be signs of improvement and straightening out.

What causes knock knees?

In most cases, there is no specific cause of knock knees because knock knees is a common normal variation during childhood. Knock knees is slightly more common in girls then boys. Obesity also can play a factor in increasing the risk of genu valgum as well. In rare occasions, rickets or osteomyelitis can contribute to knock knees.

What are the symptoms of knock knees?

The most common presentation of the knocks knees is a cosmetic deformity. Parents notice the knees touch each other while the child stands, but the ankles are spread apart. In the majority of cases, there is no pain or limitation in sports associated with knock knees. Parents tend to be concerned that the genu valgum will cause problems later on in life or limitations in activities.

What is the treatment for knock knees?

Since most cases of knock knees are a normal part of growth and development during childhood, there is no treatment necessary. Prior treatment included bracing which were thought to help straighten out the legs, but it is now known that this form of treatment does not make a difference in the outcome of the child.

In rare occasions, if the knock knees do not improve by the age of 10 years or worsens and the patient complains of significant knee pain, difficulty walking, unable to perform normal activities which may lead to arthritis later in life, surgery may be considered. Surgery is typically done before the child is done growing. Surgery consists of applying metal plates on the inside of the knees to prevent the deformity from worsening and allowing the outside of the knees to continue to grow and straighten out. Details of the surgery will be discussed with your Orthopaedic Specialist.