Genu valgum, known as knock-knees, is a knee misalignment that turns your knees inward. When people with knock-knees stand up with their knees together, there’s a gap of 3 inches or more between their ankles. This is because their knees are bent so far inward.

Genu valgum is common in young children and usually corrects itself as they grow. Up to between ages 3 and 5 have knock-knees. reports that in about 99 percent of these cases, genu valgum corrects itself by the time affected children are 7 or 8 years old.

Genu valgum can also develop later in life from:

This condition can’t be prevented, but its effects can be minimized. Physical therapy and exercise are often a successful alternative to surgery. Keep reading to learn more.

Genu valgum that persists beyond childhood may have other symptoms besides misaligned knees.

They include:

  • stiff joints
  • knee pain
  • walking with a limp

Stressed ligaments and muscles can also cause pain in your hips, ankles, or feet. If only one knee is out of line, your stance may be unbalanced.

Genu valgum is almost always a benign variation in a child’s growth. Although it occurs by chance, it seems to run in families.

Knock-knees may also be caused by:

  • injury to or infection in your knee or leg
  • bone malformation from rickets, a disease caused by lack of vitamin D and calcium
  • other bone diseases
  • obesity, which puts extra pressure on your knees
  • arthritis in your knee joints

Obesity can make genu valgum more severe, according to the . The journal reported that in a recent study, 71 percent of children with genu valgum were found to be obese.

When genu valgum is present in an older child or adult, it’s important to find out if there’s an underlying cause. A bone disease or arthritis will need to be treated.

Your doctor will ask questions about family medical history, as well as whether you’re in any pain. If you are, they’ll want to know where the pain you’re feeling is located.

During a physical exam, your doctor will observe how you stand and walk.

They’ll also look to assess:

  • inequality in your leg length
  • your knee alignment angle
  • uneven wear on the soles of your shoes

In some cases, your doctor may order an X-ray or MRI scan to look at your bone structure.

Treatment for genu valgum depends on the cause and severity of your symptoms.

For example, if rickets are causing your knock-knees, your doctor will likely prescribe vitamin D and calcium supplements to help restore your levels.

Your doctor may also prescribe prescription-strength nonsteroidal anti-inflammatory drugs if over-the-counter options, like naproxen (Aleve, Naprosyn), aren’t providing relief.

A typical treatment plan will include one or more of the following:

Weight loss

Obesity can put added stress on your knees, worsening genu valgum. If you’re overweight, your doctor will work with you to develop a healthy weight loss plan.

Check out: 10 Tips for getting started on a no-sugar diet »

Exercise

For most people with genu valgum, exercise can help realign and stabilize their knees. Your doctor or physical therapist can evaluate your gait and suggest exercises designed to strengthen your leg, hip, and thigh muscles. Specific stretches may also be useful in relieving symptoms.

Strengthening exercises can be simple, such as leg raises while seated or lying down. As you progress with an exercise routine, you may add leg weights to make it more effective.

Orthotics

If your legs are of unequal length as a result of genu valgum, a heel insert into the shoe on the shorter side can equalize your leg length and help regularize your gait. It may also relieve leg pain.

For children whose genu valgum doesn’t resolve by age 8, a brace or a splint may help guide bone growth.

Surgery

When genu valgum is severe, or when exercise isn’t enough to relieve pain and stabilize your knee, your doctor may recommend surgery.

For younger people, a small metal plate inserted in their knee can help direct future bone growth. This minor procedure is called guided growth surgery. The plate is removed when bone growth is corrected.

Adults may benefit from an osteotomy. This surgery uses permanent metal plates to keep bones aligned. This can adjust your leg bones and realign your knees.

Knee replacement surgery is also an option for older adults.

Learn more: Knee replacement evaluation and questions to ask your doctor »

In the vast majority of cases, parents can expect that a child’s genu valgum will resolve by age 8.

For older children and adults with genu valgum, a course of physical therapy and exercises can help realign their knees. It can also strengthen surrounding muscles and avoid stress damage to other joints.

If these efforts aren’t successful, surgery may be performed to realign your knees.

In time, untreated knee misalignment can cause pain and problems in functioning. One found that adults with genu valgum are at greater risk of developing osteoarthritis. See your doctor if you think you’ve got misaligned knees.