Knock knees

• Alternative Names

  Genu valgum

• Causes, incidence, and risk factors

  Most children develop a slight knock-kneed stance by the time they are 2 or 3 years old, often with significant separation at the ankles when the knees are touching. This is part of normal development and often persists through age 5 or 6, at which time the legs begin to straighten fully. By puberty, most children can stand with the knees and ankles touching (without forcing the position).

  Knock knees can also develop as a result of a disease, most often one that has already been diagnosed.

• Signs and tests

  If a doctor's examination and review of the child's medical history indicate a specific cause for the knock knees other than normal development, your health care provider will order the appropriate studies.

• Treatment

  Knock knees are usually not treated. Surgery may be considered for knock knees that persist beyond late childhood and in which the separation between the ankles is severe.

• Expectations (prognosis)

  Children normally outgrow knock knees without treatment, unless there is an underlying disease. For cases requiring surgery, the procedure provides excellent cosmetic results.

• Complications
  • 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
• Calling your health care provider

  Call your health care provider to schedule an evaluation if you suspect your child has knock knees.

• Prevention

  There is no known prevention for normal knock knees.

• References

  Sass P, Hassan G. Lower extremity abnormalities in children. Am Fam Physician. 2003 Aug 1;68(3):461-8. Review.

Review Date: 3/14/2009

Reviewed By: Neil K. Kaneshiro, MD, MHA, Clinical Assistant Professor of Pediatrics, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.