Your Child’s Knocked Knees: Everything You Need to Know


If you have a child who is dealing with knocked knees, you may be wondering what you can do to help. This website article will provide you with everything you need to know about this condition, from causes and symptoms to treatment options and prevention tips.

Genu valgum is a condition where knees bend inwards and touch (or ‘knocking’) while seated on the knees may occur. Knock knee or genus valga is a misalignment of the knee. This type of bone deformity is primarily congenital, developmental and/or posttraumatic.

What are knocked knees?

Knock knees is the name given to a condition in which the knees touch when standing with feet and ankles together. The legs appear to bow “inward.” The medical term for knock knees is genu valgum. Knock knees are very common in children, but can also affect adults. In most cases, knock knees are harmless and do not require treatment. However, in some cases, knock knees can be a sign of an underlying medical condition. If you are concerned about your knock knees (or your child’s), please consult your orthopedic surgeon for further evaluation.

Are knock knees normal?

Usually, a genu valgum is seen in children at early stages in their development. The child’s alignment often corrects with growing. It is normal for children under the age of four, and most will grow out of it by the time they reach eight or nine years old. In some cases, knock knees can be a sign of an underlying medical condition, such as rickets or arthritis. However, in most cases, it is simply a matter of the bones and joints growing at different rates. Over time, the bones will catch up to each other and the alignment will correct itself. In the meantime, there is no need for treatment, and children with knock knees can remain active and participate in all their usual activities.

Varus Valgus Knock Knee Illustration Leg Alignment

What are the symptoms of knock knee?

Symptoms can be seen when the child is standing straight with fee pointing forward:

  1. symmetric inward bowing of the knees
  2. knees touch while ankles remain apart
  3. unusual walking pattern – sometimes the knees will cross over each other

When should parents be concerned about knock knee?

If your child has knock knees along with any of the following conditions, they may have a more serious condition and should be evaluated by a knee specialist or pediatric orthopaedic surgeon:

  • knock knees that are present before age 2 years old
  • Knock knees that persist, appear, or worsen after the age 7 years old
  • asymmetric appearance of the legs (both legs aren’t the same)
  • leg lengths are different
  • knee or hip pain
  • visible limp when walking
  • height below the 5th percentile

How is knock knee diagnosed?

An orthopedic doctor and knee specialist will obtain the medial history and patient family history. They will then perform a detailed physical examination of the patient’s lower extremity, knees, and legs. Knee alignment will be assessed in the standing, sitting, and walking positions. Imaging tests including x-ray, alignment x-ray, and possible MRI or CT scan will be obtained.

Lower extremity alignment x-rays are particularly useful in diagnosing and assessing the severity of standing alignment abnormalities. These x-rays who the entire limb from the hip to the ankle, and allow assessment of the mechanical axis. Normally, the mechanical axis (line drawn from center of the hip to center of the ankle) traverses through the middle of the knee. However, with severe valgus, the line will traverse through, or outside, the lateral compartment. Aligment x-rays are a more objective way to measure leg alignment than physical examination alone.

Video Showing Knock Knee Correction Procedure

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In most cases, knock knees is a harmless condition that does not require treatment. However, in some cases, gradual correction may be recommended. This can be done with the help of braces or orthotic devices. It is also important to initiate medical treatment for any underlying medical conditions, such as bone disease, vitamin D deficiency, knee bone infection, or other underlying disease.

In severe cases, surgical correction may be necessary. Surgery involves correcting the alignment of the bones in the legs. This can help to improve the function and appearance of the legs.

Non-surgical options for knock knees

Oftentimes treatment concentrates purely on treating underlying diseases. Amongst other things rickets are treated with Vitamin D/calcium supplementation. Physical therapy can help strengthen the muscles surrounding the knee, and help maintain range of motion. Knee braces can help move the mechanical axis of the knee to a more central position and provide stability until the bones gradually grow straight.

Surgical options for knock knees

For most children, knock-knee is nothing more than a cosmetic issue, and no treatment is necessary, especially if they are dealing with slightly knocked knees. However, in some cases, the condition can lead to pain or difficulty walking. For these children, surgery may be recommended. There are two main types of surgery for knock-knee: growth plate tethering and distal femoral osteotomy.

Hemi-epiphysiodesis (Guided Growth)

Growth plate tethering or hemi-epiphysiodesis involves shutting down one side of the growth plate near the knee so that the other side can catch up. This is also known as guided growth surgery. This is usually done with small staples that can be removed at a later date.

The initiation of treatment and the amount of time the staples remain in place in the knee depends on the degree of malalignment, the age of the patient, the growth rate of the patient, and expected remaining growth. The surgery is usually performed as the child is approaching puberty (age 11 for females and 13 for males).

Distal femoral osteotomy (DFO)

Distal femoral osteotomy involves cutting and repositioning the thighbone (femur) itself. This can be done as an opening wedge or closing wedge osteotomy. A plate and screws are usually used as internal fixation to hold the bone in place while it heals. This procedure is more commonly used in adult patients who do not have any growth remaining. In some cases this surgery can be combined with limb lengthening or limb shortening procedures.

If surgery is recommended for your child’s malalignment, the type of surgery recommended will depend on the severity of the condition and the age of the child. In most cases, surgery is successful in correcting knock-knee and allowing children to resume normal activities.

In some cases, distal femoral osteotomy may be combined with other surgeries to treat cartilage damage.

What is the long-term outlook for children with knock knee

Even without treatment, the vast majority of children with knock knees get better and have a favorable long-term prognosis. The outlook is also good for patients who have surgery for severe forms of the condition. Surgical and non-surgical therapies are generally considered safe, and children’s bones heal faster and more predictably than adults’ bones.

Children with severe knock knees that do not improve or are caused by an underlying disease (pathological valgus) who do not receive treatment may develop knee pain, meniscal tears, patellar dislocation, or cartilage damage (arthritis) as they get older. Young adults with pathologic knee valgus (knock knees in adulthood) should be evaluated for potential treatment options.

FAQ. Frequently Asked Questions

Can knocked knees be corrected?

Yes, knocked knees can be corrected. In adults, this procedure is known as distal femoral osteotomy (DFO).

What are the causes of knock knee?

Knock knee can occur due to either too rapid of growth of one side of the growth plate, or too slow of growth of one side of the growth plate. Some degree of knock knee is normal in children. Pathologic valgus (excessive or persistent knock knee) can be due to underlying conditions such as arthritis and rickets.

How do you get rid of knock knees?

Most of the time, knock knees will resolve on their own as children grow into adulthood. However, in some cases the alignment problem persists or is very severe.

In these cases, surgery may be needed to correct the valgus knee alignment. In younger patients (age 10-13) guided growth can be used to help realign the bone as the patient is growing. In adult patients, osteotomy surgery (realignment of the bone) can be performed to straighten out the leg.

Is it normal to have knocked knees?

Slight valgus, or knocked knees, is generally considered within normal limits. This is more common in females and in children. In some cases, the knock knees is severe enough that it causes pain, functional limitations, or can lead to knee problems later in life, such as arthritis.

Dr. Burnham is a board-certified orthopedic surgeon who had fellowship training in complex knee surgeries, such as distal femoral osteotomy and tibial tubercle transfer. He specializes in non-knee replacement knee surgery, also known as knee preservation surgery. Dr. Burnham is located in Louisiana and sees patients from the Baton Rouge, Hammond, Brusly, Denham Springs, Walker, Livingston, Prairieville, Gonzales, New Roads, Zachary, Central, St. Francisville, Woodville, Centreville, Alexandria, Lafayette, and Natchez areas of Louisiana and Mississippi.

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