Site Map

Knock knees

Genu valgum

Knock knees are condition in which the knees touch, but the ankles do not touch. The legs turn inward.

I Would Like to Learn About:

Causes

Infants start out with bowlegs because of their folded position while in their mother's womb. The legs begin to straighten once the child starts to walk (at about 12 to 18 months). By age 3, the child becomes knock-kneed. When the child stands, the knees touch but the ankles are apart.

By puberty, the legs straighten out and most children can stand with the knees and ankles touching (without forcing the position).

Knock knees can also develop as a result of a medical problem or disease, such as:

• Injury of the shinbone (only one leg will be knock-kneed)
• Osteomyelitis (bone infection)
• Overweight or obesity
• Rickets (a disease caused by a lack of vitamin D)

Exams and Tests

A health care provider will examine your child. Tests will be done if there are signs that knock knees are not a part of normal development.

Treatment

Knock knees are not treated in most cases.

If the problem continues after age 7, the child may use a night brace. This brace is attached to a shoe.

Surgery may be considered for knock knees that are severe and continue beyond late childhood.

Outlook (Prognosis)

Children normally outgrow knock knees without treatment, unless it is caused by a disease.

If surgery is needed, the results are most often good.

Possible Complications

Complications may include:

• Difficulty walking (very rare)
• Self-esteem changes related to cosmetic appearance of knock knees
• If left untreated, knock knees can lead to early arthritis of the knee

When to Contact a Medical Professional

Contact your provider if you think your child has knock knees.

Prevention

There is no known prevention for normal knock knees.

References

McClincy MP, Olgun ZD, Dede O. Orthopedics. In: Zitelli BJ, McIntire SC, Nowalk AJ, Garrison J, eds. Zitelli and Davis' Atlas of Pediatric Physical Diagnosis. 8th ed. Philadelphia, PA: Elsevier; 2023:chap 22.

Pomeranz AJ, Sabnis S, Busey SL, Kliegman RM. Bowlegs and knock-knees. In: Pomeranz AJ, Sabnis S, Busey SL, Kliegman RM, eds. Pediatric Decision-Making Strategies. 2nd ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 49.

Winell JJ, Baldwin KD, Wells L. Torsional and angular deformities of the limb. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 695.

Wimberly RL. Disorders of the leg. In: Herring JA, ed. Tachdjian’s Pediatric Orthopaedics. 6th ed. Philadelphia, PA: Elsevier; 2022:chap 18.

BACK TO TOP

Review Date: 10/31/2022  

Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Professor of Pediatrics, University of Washington School of Medicine, Seattle, WA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

Health Content Provider 06/01/2025

A.D.A.M., Inc. is accredited by URAC, for Health Content Provider (www.urac.org). URAC's accreditation program is an independent audit to verify that A.D.A.M. follows rigorous standards of quality and accountability. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial policy, editorial process and privacy policy. A.D.A.M. is also a founding member of Hi-Ethics. This site complied with the HONcode standard for trustworthy health information from 1995 to 2022, after which HON (Health On the Net, a not-for-profit organization that promoted transparent and reliable health information online) was discontinued.

The information provided herein should not be used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed medical professional should be consulted for diagnosis and treatment of any and all medical conditions. Links to other sites are provided for information only -- they do not constitute endorsements of those other sites. © 1997- 2024 A.D.A.M., a business unit of Ebix, Inc. Any duplication or distribution of the information contained herein is strictly prohibited.