Bow Legs and Knock Knees in Children: Causes, Symptoms, and Treatment

Bow legs and knock knees are common growth conditions that influence how a child’s legs align and develop over time.

In bow legs (genu varum), the knees stay apart even when the ankles are together. This gives the legs a curved appearance. In knock knees (genu valgum), the knees touch, but the ankles stay apart.

Both conditions are a normal part of growth and development in most children. All babies are born with bow legs, which are most visible when they begin to walk around 12 months of age. As the child grows, the legs usually straighten out by the age of 2. Between ages 2 to 3, the knees may begin to turn inward, making the child appear knock-kneed. This stage is most noticeable between ages 3 and 4.

By the time a child is 7 years old, the leg shape usually becomes normal with a mild inward angle of 5 to 9 degrees, which remains throughout adulthood.

When to Be Concerned

A small amount of bowing or knocking is completely normal and should not cause pain. However, it’s best to see a pediatric orthopedist if your child shows any of the following signs:

• Bow legs that remain after age 3 or appear to be getting worse.
• Knock knees that remain beyond age 8 or appear before age 2.
• A large difference between the shape of one leg and the other.
• Knee angles greater than 15 degrees.
• Pain, limping, or trouble walking and running.
• Bow legs or knock knees that do not improve after 12 months.

Children who are overweight or have loose ligaments may appear more knock-kneed. Encouraging your child to stay active and maintain a healthy weight can promote normal leg alignment.

Causes

While normal growth is the most common cause, sometimes these conditions may be linked to other health problems such as:

• Blount’s disease – a growth plate disorder in the shinbone that causes the leg to curve.
• Rickets – A bone disorder that occurs due to insufficient levels of vitamin D, calcium, or phosphorus.
• Bone infection or metabolic disease.
• Fractures that heal in an abnormal shape.
• Genetic or congenital conditions.

Diagnosis

Doctors usually diagnose bow legs and knock knees with a physical examination. They will check your child’s leg shape, movement, and walking pattern.

If your child is over 2 years old or one leg looks more affected, the doctor may recommend an X-ray to look at the bones and growth plates. Blood tests may be done to check for vitamin D or other nutrient deficiencies if rickets is suspected.

X-rays are usually not needed for children under 7 years old unless there is pain, unevenness between the legs, or limited movement.

Treatment Options

In most cases, children with bow legs or knock knees recover naturally without needing any treatment. Their legs straighten naturally as they grow. Special braces, splints, or shoes are not helpful and are not recommended.

However, in some cases, further evaluation and treatment may be needed:

Non-Surgical Treatment

If the condition is caused by an underlying issue like rickets, treatment includes vitamin D and calcium supplements. A nutritious diet combined with a healthy body weight plays an important role in keeping bones strong.

Surgical Treatment

Surgery is considered only in severe cases that do not improve with growth or in children with underlying bone diseases.

The type of surgery depends on the child’s age and bone growth:

• In younger children with open growth plates, doctors may perform guided growth surgery, where small plates or staples are used to control bone growth and gradually correct the alignment.
• In older children or teenagers, the bones may need to be cut and realigned using metal plates, pins, or screws to hold them in place as they heal.

These surgeries have high success rates but are done only when clearly needed.

Monitoring at Home

Parents can take a photo of their child’s legs every six months to track improvement. This helps you and your doctor monitor whether the leg shape is changing naturally.

You should contact your doctor if:

• The bowing or knocking becomes worse.
• One leg appears more affected than the other.
• Your child develops pain, limping, or difficulty walking.

Conclusion

Most kids with bow legs or knock knees eventually develop normal, well-aligned legs, and these conditions seldom lead to lasting issues. The conditions rarely cause long-term problems.

If diagnosed and treated early, children with Blount’s disease or rickets also do very well. However, untreated severe cases may lead to joint strain or an increased risk of arthritis later in life.

Mild bow legs and knock knees are a normal part of growth and development in children. In most cases, they correct themselves without any treatment. However, if your child’s leg shape seems severe, uneven, or causes pain, it’s best to consult a pediatric orthopedic specialist for proper evaluation and care.